Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attribu...Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attributes encompassing molecular magnetism[1],photoluminescence[2],and catalysis[3].Organic ligands play a crucial role in effectively shielding these NCs,serving two primary functions:firstly,vital in preventing NC aggregation,particularly for the formation of robust single-crystal structures;secondly,acting as either bridging or peripheral structural components of NCs[4].This characterization of organic-inorganic hybridization offers unique advantages for unraveling the intricate relationships between structure and properties[5].展开更多
Quantum integrability provides a unique and powerful framework for accurately understanding quantum magnetism.In this review,we focus specifically on several quantum integrable low-dimensional quantum Ising models.We ...Quantum integrability provides a unique and powerful framework for accurately understanding quantum magnetism.In this review,we focus specifically on several quantum integrable low-dimensional quantum Ising models.We begin with the transverse field Ising chain(TFIC)at quantum critical point and examine how it evolves under perturbations,such as an applied longitudinal field or weak coupling to another quantum critical TFIC.展开更多
Annealing has been a popular method to improve the soft magnetism of metallic glasses (MGs), which however usually makes MGs brittle and difficult to process. Here, it is demonstrated that the embrittled Fe-based MG c...Annealing has been a popular method to improve the soft magnetism of metallic glasses (MGs), which however usually makes MGs brittle and difficult to process. Here, it is demonstrated that the embrittled Fe-based MG can be reductilized and the coercivity can be further lowered through the rejuvenation of memory effect. The synchronous improvement in the plasticity and soft magnetic properties is attributed to the combination effects of releasing much residual stress, decreasing the magnetic anisotropy, and homogenizing the glasses during the rejuvenation process. The current work opens a new perspective to improve the properties of MGs by utilizing the memory effect and holds promising commercial application potential.展开更多
Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsit...Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.展开更多
Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.A...Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.Among these materials,fully compensated ferrimagnets are particularly promising due to their unique characteristics such as the magneto-optical efect,completely spin-polarized currents,and the anomalous Hall efect.We performed a structural search on 2D unconventional stoichiometric Cr-I crystals using a global optimization algorithm.The most stable CrI-P21/m monolayer is a fully compensated ferrimagnetic semiconductor with a band gap of 1.57 eV and a high magnetic transition temperature of 592 K.The spontaneous spin splitting in CrI-P21/m originates from the inequivalent local coordination environments of Cr^(1)and Cr^(2)ions,yielding a mismatch in their 3d orbitals splitting.Notably,carrier doping at a concentration of 0.01 electrons or holes per atom enables reversible spin polarization,generating a fully spin-polarized current in CrI-P21/m.This performance makes it a highly promising candidate for spintronic devices.Our fndings not only provide a structural paradigm for discovering fully compensated ferrimagnets but also open a new avenue for designing zero-moment magnetic materials with intrinsic spin splitting.展开更多
FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in F...FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in FeSe.FeSe is recognized as a prototypical platform for competing magnetic interactions,including Néel,stripe,and staggered antiferromagnetic coupling.However,the correlations between these magnetic orders and how they change with varying environmental conditions require further study.Here,we calculated the magnetic order of monolayer FeSe in three diferent environments:pure one,with slight lattice distortion,and on SrTiO_(3) substrate,by frst principles calculations.We fnd that in the calculated dispersion relation E(q)between the spin spiral energy E and spin spiral vector q of the monolayer FeSe structure,the stripe magnetic order M(π/2,π/2)has the lowest energy,and there is a fat E(q)between the wave vector X(π/2,0)and Néel magnetic order 2X(π,0),which are the degenerate E(q)states.The ground state of M and the highest density of states around 2X may be the reason for the competition of two magnetic orders.The slight lattice distortion does not alter the magnetic properties of monolayer FeSe.When monolayer FeSe is attached to the SrTiO_(3)substrate,the degenerate E(q)is still retained;meanwhile,the energy of the 2X(π,0)state is closer to the M state,which may be one of the reasons for the increase of superconducting temperature in FeSe/SrTiO_(3).展开更多
Frustrated lanthanide oxides with dense magnetic lattice and suppressed ordering temperature have potential applications in cryogenic magnetic refrigeration.Herein,the crystal structure,magnetic properties,magnetic ph...Frustrated lanthanide oxides with dense magnetic lattice and suppressed ordering temperature have potential applications in cryogenic magnetic refrigeration.Herein,the crystal structure,magnetic properties,magnetic phase transition(MPT)together with magnetocaloric effect(MCE)of LnOF(Ln=Gd,Dy,Ho,and Er)compounds were investigated.Crystallographic study shows that these compounds crystallize in the centrosymmetric space group R3m with an ideal triangular lattice.No long-range magnetic ordering is observed above 2 K for LnOF(Ln=Gd,Ho,and Er).However,DyOF compound undergoes an MPT from paramagnetic(PM)to antiferromagnetic(AFM)at the Neel temperature(TN≈4 K).Considerable reversible MCE is observed in these triangular-lattice compounds.Under the magnetic field change(μ0ΔH)of 0-2 T,the maximum values of magnetic entropy change(-ΔSMmax)of them are 6.1,9.4,12.7,and 14.1 J/(kg·K),respectively.Interestingly,the value of ErOF with Ising-like spin is 2.3 times that of GdOF,which provides an approach for exploring magnetic refrigerants with excellent low-field cryogenic magnetocaloric effect.展开更多
Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These de...Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These densely arranged particles with a consistent planar orientation significantly enhance the soft magnetic properties of SMCs,including high permeability and low magnetic losses.The internal structures of the composites and microstructure evolution of the flaky nanocrystalline particles during the hot-pressing process have been thoroughly studied.Moreover,systematic investigations into the effects of coatings and particle sizes on the maximum permeability and magnetic losses of the composites are conducted.The SMC prepared using the coated particles with a size of 0-100μm exhibits a high maximum perme-ability of 2170(at 1000 Hz)and low magnetic loss of 41.61 W kg^(-1)(at 1000 Hz and 1.0 T).The losses and permeability analysis reveal that the superior performance of these soft magnetic materials is attributed to their laminated structure,insulation coating,and the reduced planar demagnetizing factor.Compared to the traditional silicon steel,this novel SMCs exhibits high magnetic permeability and reduced magnetic losses at frequencies above 1000 Hz,which possess immense application potential within high-frequency electric machines.展开更多
The microstructure of(Nd,Ce)-Fe-B sintered magnets with different diffusion depths was characterized by a magnetic force microscope,and the relationship between the magnetic properties and the local structure of grain...The microstructure of(Nd,Ce)-Fe-B sintered magnets with different diffusion depths was characterized by a magnetic force microscope,and the relationship between the magnetic properties and the local structure of grain boundary diffused magnets is discussed.The domains perpendicular to the c-axis(easy magnetization direction)show a typical maze-like pattern,while those parallel to the c-axis show the characte ristics of plate domains.The significant gradient change is shown in the concentration of Dy with the direction of diffusion from the surface to the interior.Dy diffuses along grain boundaries and(Dy,Nd)_(2)Fe_(14)B layer with a high anisotropy field formed around the grains.Through in-situ electron probe micro-analysis/magnetic force microscopy(EPMA/MFM),it is found that the average domain width decreases,and the proportion of single domain grains increases as diffusion depth increases.This is caused by both the change of concentration and distribution of Dy.The grain boundary diffusion process changes the microstructure and microchemistry inside the magnet,and these local magnetism differences can be reflected by the configuration of the magnetic domain structure.展开更多
Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,...Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.展开更多
A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_...A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,7-C_(2)B_(9)H_(11))2](m-Dy)were synthesized by using the isomeric dicarbollide ligands,namely[nido-7,8-C2BgH_(11)]^(2-)and[nido-7,9-C_(2)B_(9)H_(11)]^(2-).The structural details of o/m-Dy and m-Dy and magnetic dynamics of m-Dy were investigated to compare with the previous study on[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,2-C_(2)B_(9)H_(11))_(2)]o-Dy.The bending angles of sandwiched dysprosiacarboranes are straightened so as to improve energy bar-riers(U_(eff))from 430(5)to 591(0)K.Magneto-structural correlations show that the introduction of meta-C sites within the π-electron delocalized heterocyclic ring can effectively shorten the Dy-C_(2)B_(3)centroid distance and increase the C_(2)B_(3)centroid...Dy...C_(2)B_(3)centroid bending angle which is attributed to the dif-ferences in electronegativity between C and B atoms on the ring of C_(2)B_(3)^(2-).Therefore,to further enhance the performance of single-molecule magnets(SMMs)on this basis,future endeavors should focus on diminishing the equatorial solvent molecules to make a wider C2B3...Dy...C_(2)B_(3)bending angle.展开更多
The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this st...The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.展开更多
Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in...Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.展开更多
The electronic structure,elasticity,and magnetic properties of the Mn_(2)XIn(X=Fe,Co)full-Heusler compounds are comprehensively investigated via first-principles calculations.The calculated elastic constants indicate ...The electronic structure,elasticity,and magnetic properties of the Mn_(2)XIn(X=Fe,Co)full-Heusler compounds are comprehensively investigated via first-principles calculations.The calculated elastic constants indicate that both Mn_(2)FeIn and Mn_(2)Co In possess ductility.At the optimal lattice constants,the magnetic moments are found to be 1.40μB/f.u.for Mn_(2)FeIn and 1.69μB/f.u.for Mn_(2)CoIn.Under the biaxial strain ranging from-2%to 5%,Mn_(2)FeIn demonstrates a remarkable variation in the spin polarization,spanning from-2%to 74%,positioning it as a promising candidate for applications in spintronic devices.Analysis of the electronic structure reveals that the change in spin polarization under strain is due to the shift of the spin-down states at the Fermi surface.Additionally,under biaxial strain,the magnetic anisotropy of Mn_(2)FeIn undergoes a transition of easy-axis direction.Utilizing second-order perturbation theory and electronic structure analysis,the variation in magnetic anisotropy with strain can be attributed to changes of d-orbital states near the Fermi surface.展开更多
Refrigeration in the liquid helium temperature range provides vital technological support for many scientific frontiers and engineering technologies.The considerable magnetocaloric effect(MCE)makes EuTiO_(3)a potentia...Refrigeration in the liquid helium temperature range provides vital technological support for many scientific frontiers and engineering technologies.The considerable magnetocaloric effect(MCE)makes EuTiO_(3)a potential candidate for magnetic refrigeration near liquid helium temperature.More interestingly,the magnetic transition from antiferromagnetism to ferromagnetism offers the possibility to tailor the magnetism and improve the MCE of this magnetic system.In this study,the magnetic properties and MCE of EuTi_(0.875)Zr_(0.125)O_(3)were systematically investigated by first-principles calculation and experiments.The substitution of Zr induces a significant lattice expansion and alters the electronic interactions,leading to a dominance of ferromagnetism in the compound.Remarkable low-field MCE performance has been achieved attributed to the enhanced ferromagnetism and low saturation field.Under the field change of 0-1 T,the maximum magnetic entropy change(−△S_(M)^(max))and adiabatic temperature change(△T_(ad)^(max))are 17.9 J kg^(-1)K^(-1)and 6.1 K,respectively.It is worth noting that the−△S_(M)^(max)of EuTi_(0.875)Zr_(0.125)O_(3)reaches 10.3 J kg^(-1)K^(-1)for a field change of 0-0.5 T,making it one of the best magnetocaloric materials ever reported operating in the liquid helium temperature range.展开更多
Group IV element Pb has been selected as the dopant to dope at the Sr site of Sr_(2)IrO_(4). It is exciting to find that the single-phase crystal structure could be maintained with a high Pb doping level of up to x=0....Group IV element Pb has been selected as the dopant to dope at the Sr site of Sr_(2)IrO_(4). It is exciting to find that the single-phase crystal structure could be maintained with a high Pb doping level of up to x=0.3 in Sr_(2-x)Pb_(x)IrO_(4). The mapping data obtained from energy-dispersive x-ray spectroscopy analyses give solid evidence that the Pb ions are uniformly distributed in the Sr_(2)IrO_(4) matrix. The incorporation of Pb leads to a moderate depression of the canted antiferromagnetic ordering state. The electrical conductivity could be greatly enhanced when the Pb doping content is higher than x=0.2.The present results give a fresh material base to explore new physics in doped Sr_(2)IrO_(4) systems.展开更多
Topological magnetism with strong robustness,nanoscale dimensions and ultralow driving current density(106 A/m^(2))is promising for applications in information sensing,storage,and processing,and thus sparking widespre...Topological magnetism with strong robustness,nanoscale dimensions and ultralow driving current density(106 A/m^(2))is promising for applications in information sensing,storage,and processing,and thus sparking widespread research interest.Exploring candidate material systems with nanoscale size and easily tunable properties is a key for realizing practical topological magnetism-based spintronic devices.Here,we propose a class of ultrathin heterostructures,Fe/Bi_(2)O_(2)X(X=S,Se,Te)by deposing metal Fe on quasi-two-dimensional(2D)bismuth oxychalcogenides Bi_(2)O_(2)X(X=S,Se,Te)with excellent ferroelectric/ferroelastic properties.Large Dzyaloshinskii–Moriya interaction(DMI)and topological magnetism can be realized.Our atomistic spin dynamics simulations demonstrate that field-free vortex–antivortex loops and sub-10 nm skyrmions exist in Fe/Bi_(2)O_(2)S and Fe/Bi_(2)O_(2)Se interfaces,respectively.These results provide a possible strategy to tailor topological magnetism in ultrathin magnets/2D materials interfaces,which is extremely vital for spintronics applications.展开更多
We investigate the evolution of magnetic properties as well as the content and distribution of Mn for Mn(Sb_(1-x)Bi_(x))_(2)Te_(4) single crystals grown by large-temperature-gradient chemical vapor transport method.It...We investigate the evolution of magnetic properties as well as the content and distribution of Mn for Mn(Sb_(1-x)Bi_(x))_(2)Te_(4) single crystals grown by large-temperature-gradient chemical vapor transport method.It is found that the ferromagnetic MnSb_(2)Te_(4) changes to antiferromagnetism with Bi doping when x≥0.25.Further analysis implies that the occupations of Mn ions at Sb/Bi site Mn_(Sb/Bi) and Mn site Mn_(Mn) have a strong influence on the magnetic ground states of these systems.With the decrease of Mn_(Mn) increase of Mn_(Sb/Bi),the system will favor the ferromagnetic ground state.In addition,the rapid decrease of T_(C/N) with increasing Bi content when x ≤0.25 and the insensitivity of T_(N) to x when x> 0.25 suggest that the main magnetic interaction may change from the Ruderman-Kittel-Kasuya-Yosida type at low Bi doping region to the van-Vleck type in high Bi doped samples.展开更多
After the discovery of the ARECh_(2)(A=alkali or monovalent ions,RE=rare-earth,Ch=chalcogen)triangular lattice quantum spin liquid(QSL)family,a series of its oxide,sulfide,and selenide counterparts has been consistent...After the discovery of the ARECh_(2)(A=alkali or monovalent ions,RE=rare-earth,Ch=chalcogen)triangular lattice quantum spin liquid(QSL)family,a series of its oxide,sulfide,and selenide counterparts has been consistently reported and extensively investigated.While KErTe_(2) represents the initial synthesized telluride member,preserving its triangular spin lattice,it was anticipated that the substantial tellurium ions could impart more pronounced magnetic attributes and electronic structures to this material class.This study delves into the magnetism of KErTe_(2) at finite temperatures through magnetization and electron spin resonance(ESR)measurements.Based on the angular momentum J after spin-orbit coupling(SOC)and symmetry analysis,we obtain the magnetic effective Hamiltonian to describe the magnetism of Er^(3+)in R3m space group.Applying the mean-field approximation to the Hamiltonian,we can simulate the magnetization and magnetic heat capacity of KErTe_(2) in paramagnetic state and determine the crystalline electric field(CEF)parameters and partial exchange interactions.The relatively narrow energy gaps between the CEF ground state and excited states exert a significant influence on the magnetism.For example,small CEF excitations can result in a significant broadening of the ESR linewidth at 2 K.For the fitted exchange interactions,although the values are small,given a large angular momentum J=15/2 after SOC,they still have a noticeable effect at finite temperatures.Notably,the heat capacity data under different magnetic fields along the𝑐axis direction also roughly match our calculated results,further validating the reliability of our analytical approach.These derived parameters serve as crucial tools for future investigations into the ground state magnetism of KErTe_(2).The findings presented herein lay a foundation for exploration of the intricate magnetism within the triangular-lattice delafossite family.展开更多
Functional materials with multiple properties are urgent to be explored to reach high requirements for applications nowadays.In this work,a new multifunctional one-dimensional(1D)chain compound[N(C_(3)H_(7))_(4)][Cu(o...Functional materials with multiple properties are urgent to be explored to reach high requirements for applications nowadays.In this work,a new multifunctional one-dimensional(1D)chain compound[N(C_(3)H_(7))_(4)][Cu(ohpma)]·H_(2)O 1(ohpma=deprotonated N-(2-hydoxyphenyl)oxamic acid)exhibiting both 1D antiferromagnetic and nonlinear optical properties,which are both originated from the same polar[Cu(C_(8)H_(4)NO_(4))]magnetic units,has been successfully synthesized by evaporation at room temperature.Bis-polydentate nature of the(ohpma)3−ligand with constrained tridentate and bidentate coordination sites conducts Cu^(2+)ions coordinating in different geometries and forms 1D chains along the c axis,which are further separated by the[N(C_(3)H_(7))_(4)]+cations.And the 1D magnetic chains further exhibit noncentrosymmetric polar arrangement.Nonlinear optical study shows polar compound 1 exhibits a discernible second-harmonic generation(SHG)efficiency and the calculation of the partial density of states indicates that the SHG efficiency of 1 is mainly originated from the polar[Cu(C_(8)H_(4)NO_(4))]magnetic units.Moreover,magnetic susceptibility shows a broad maximum around 70 K with strong intrachain interaction of J/k B=−113.0 K but no long-range order is observed down to 2 K,suggesting that 1 shows a good 1D magnetism.Both good 1D magnetism and SHG activity suggest that 1 could be as a potential multifunctional material,particularly.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.22171094,21925104,92261204,and 22431005)Hubei Provincial Science and Technology Innovation Team Project[2022]The National Key R&D Program of China(No.2022YFB3807700)。
文摘Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attributes encompassing molecular magnetism[1],photoluminescence[2],and catalysis[3].Organic ligands play a crucial role in effectively shielding these NCs,serving two primary functions:firstly,vital in preventing NC aggregation,particularly for the formation of robust single-crystal structures;secondly,acting as either bridging or peripheral structural components of NCs[4].This characterization of organic-inorganic hybridization offers unique advantages for unraveling the intricate relationships between structure and properties[5].
基金supported by the National Natural Science Foundation of China Grant Nos.12450004,12274288the Innovation Program for Quantum Science and Technology Grant No.2021ZD0301900。
文摘Quantum integrability provides a unique and powerful framework for accurately understanding quantum magnetism.In this review,we focus specifically on several quantum integrable low-dimensional quantum Ising models.We begin with the transverse field Ising chain(TFIC)at quantum critical point and examine how it evolves under perturbations,such as an applied longitudinal field or weak coupling to another quantum critical TFIC.
基金support from the National Natural Science Foundation of China(No.52231006)Junqiang Wang acknowledges financial support from the National Key R&D Program of China(No.2018YFA0703600)the National Natural Science Foundation of China(Nos.92163108 and 52222105).
文摘Annealing has been a popular method to improve the soft magnetism of metallic glasses (MGs), which however usually makes MGs brittle and difficult to process. Here, it is demonstrated that the embrittled Fe-based MG can be reductilized and the coercivity can be further lowered through the rejuvenation of memory effect. The synchronous improvement in the plasticity and soft magnetic properties is attributed to the combination effects of releasing much residual stress, decreasing the magnetic anisotropy, and homogenizing the glasses during the rejuvenation process. The current work opens a new perspective to improve the properties of MGs by utilizing the memory effect and holds promising commercial application potential.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403800 and 2023YFA1407300)the National Natural Science Foundation of China(Grant Nos.12374153,12447101,and 11974362)supported by the U.S.Department of Energy,Basic Energy Sciences(Grant No.DE-FG02-99ER45747)。
文摘Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.
基金supported by the Natural Science Foundation of Wenzhou Institute,University of Chinese Academy of Sciences(UCAS)(Grant No.WIUCASQD2023004)the National Natural Science Foundation of China(Grant Nos.12304006,12404265,and 12435001)+2 种基金the Natural Science Foundation of Shanghai,China(Grant No.23JC1401400)the Natural Science Foundation of Wenzhou(Grant No.L2023005)the Fundamental Research Funds for the Central Universities of East China University of Science and Technology。
文摘Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.Among these materials,fully compensated ferrimagnets are particularly promising due to their unique characteristics such as the magneto-optical efect,completely spin-polarized currents,and the anomalous Hall efect.We performed a structural search on 2D unconventional stoichiometric Cr-I crystals using a global optimization algorithm.The most stable CrI-P21/m monolayer is a fully compensated ferrimagnetic semiconductor with a band gap of 1.57 eV and a high magnetic transition temperature of 592 K.The spontaneous spin splitting in CrI-P21/m originates from the inequivalent local coordination environments of Cr^(1)and Cr^(2)ions,yielding a mismatch in their 3d orbitals splitting.Notably,carrier doping at a concentration of 0.01 electrons or holes per atom enables reversible spin polarization,generating a fully spin-polarized current in CrI-P21/m.This performance makes it a highly promising candidate for spintronic devices.Our fndings not only provide a structural paradigm for discovering fully compensated ferrimagnets but also open a new avenue for designing zero-moment magnetic materials with intrinsic spin splitting.
基金supported by the National Natural Science Foundation of China(Grant Nos.11204131 and 11974181)。
文摘FeSe is an Fe-based paramagnetic superconductor with the simplest structure.The competition between the Néel and stripe magnetic orders is believed to be one of the reasons for the absence of magnetic orders in FeSe.FeSe is recognized as a prototypical platform for competing magnetic interactions,including Néel,stripe,and staggered antiferromagnetic coupling.However,the correlations between these magnetic orders and how they change with varying environmental conditions require further study.Here,we calculated the magnetic order of monolayer FeSe in three diferent environments:pure one,with slight lattice distortion,and on SrTiO_(3) substrate,by frst principles calculations.We fnd that in the calculated dispersion relation E(q)between the spin spiral energy E and spin spiral vector q of the monolayer FeSe structure,the stripe magnetic order M(π/2,π/2)has the lowest energy,and there is a fat E(q)between the wave vector X(π/2,0)and Néel magnetic order 2X(π,0),which are the degenerate E(q)states.The ground state of M and the highest density of states around 2X may be the reason for the competition of two magnetic orders.The slight lattice distortion does not alter the magnetic properties of monolayer FeSe.When monolayer FeSe is attached to the SrTiO_(3)substrate,the degenerate E(q)is still retained;meanwhile,the energy of the 2X(π,0)state is closer to the M state,which may be one of the reasons for the increase of superconducting temperature in FeSe/SrTiO_(3).
基金Project supported by the National Key Research and Development Program of China(2022YFB3505101)the National Science Foundation for Excellent Young Scholars(52222107)+2 种基金the National Science Foundation for Distinguished Young Scholars(51925605)the National Natural Science Foundation of China(52171195)the Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055B002)。
文摘Frustrated lanthanide oxides with dense magnetic lattice and suppressed ordering temperature have potential applications in cryogenic magnetic refrigeration.Herein,the crystal structure,magnetic properties,magnetic phase transition(MPT)together with magnetocaloric effect(MCE)of LnOF(Ln=Gd,Dy,Ho,and Er)compounds were investigated.Crystallographic study shows that these compounds crystallize in the centrosymmetric space group R3m with an ideal triangular lattice.No long-range magnetic ordering is observed above 2 K for LnOF(Ln=Gd,Ho,and Er).However,DyOF compound undergoes an MPT from paramagnetic(PM)to antiferromagnetic(AFM)at the Neel temperature(TN≈4 K).Considerable reversible MCE is observed in these triangular-lattice compounds.Under the magnetic field change(μ0ΔH)of 0-2 T,the maximum values of magnetic entropy change(-ΔSMmax)of them are 6.1,9.4,12.7,and 14.1 J/(kg·K),respectively.Interestingly,the value of ErOF with Ising-like spin is 2.3 times that of GdOF,which provides an approach for exploring magnetic refrigerants with excellent low-field cryogenic magnetocaloric effect.
基金supported by the National Natural Science Foundation of China(Grant No.52071294)the National Key Research and Development Program(Grant No.2022YFE0109800)the Natural Science Foundation of Zhejiang Province(Grant No.LY20E020015).
文摘Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These densely arranged particles with a consistent planar orientation significantly enhance the soft magnetic properties of SMCs,including high permeability and low magnetic losses.The internal structures of the composites and microstructure evolution of the flaky nanocrystalline particles during the hot-pressing process have been thoroughly studied.Moreover,systematic investigations into the effects of coatings and particle sizes on the maximum permeability and magnetic losses of the composites are conducted.The SMC prepared using the coated particles with a size of 0-100μm exhibits a high maximum perme-ability of 2170(at 1000 Hz)and low magnetic loss of 41.61 W kg^(-1)(at 1000 Hz and 1.0 T).The losses and permeability analysis reveal that the superior performance of these soft magnetic materials is attributed to their laminated structure,insulation coating,and the reduced planar demagnetizing factor.Compared to the traditional silicon steel,this novel SMCs exhibits high magnetic permeability and reduced magnetic losses at frequencies above 1000 Hz,which possess immense application potential within high-frequency electric machines.
基金Project supported by the National Key Research and Development Program of China(2021YFB3503003,2021YFB3503100,2022YFB3505401)。
文摘The microstructure of(Nd,Ce)-Fe-B sintered magnets with different diffusion depths was characterized by a magnetic force microscope,and the relationship between the magnetic properties and the local structure of grain boundary diffused magnets is discussed.The domains perpendicular to the c-axis(easy magnetization direction)show a typical maze-like pattern,while those parallel to the c-axis show the characte ristics of plate domains.The significant gradient change is shown in the concentration of Dy with the direction of diffusion from the surface to the interior.Dy diffuses along grain boundaries and(Dy,Nd)_(2)Fe_(14)B layer with a high anisotropy field formed around the grains.Through in-situ electron probe micro-analysis/magnetic force microscopy(EPMA/MFM),it is found that the average domain width decreases,and the proportion of single domain grains increases as diffusion depth increases.This is caused by both the change of concentration and distribution of Dy.The grain boundary diffusion process changes the microstructure and microchemistry inside the magnet,and these local magnetism differences can be reflected by the configuration of the magnetic domain structure.
基金supported by the National Key Research and Development Program of China(No.2022YFB3505301)the National Key Research and Development Program of Shanxi Province(No.202302050201014)+2 种基金the National Natural Science Foundation of China(No.12304148)the Natural Science Basic Research Program of Shanxi Province(No.202203021222219)the China Postdoctoral Science Foundation(No.2023M731452).
文摘Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.
基金the National Natural Science Foundation of China(22375157)the Programme of Introducing Talents of Discipline to Universities(B23025)+4 种基金State Key Laboratory of Electrical Insulation and Power Equipment(EIPE23402,EIPE23405)SpecialSupportPlanof ShaanxiProvincefor Young Top-notch Talent,the Fundamental Research Funds for Central Universities(xtr052023002,xzy012023024)the China Postdoctoral Science Foundation(2023M742783)Shaanxi Postdoctoral Science Foundation(2023BSHYDZZ12)the"Scientists+engineers"Team Building Project of Qin Chuang Yuan(2022KXJ-088).
文摘A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,7-C_(2)B_(9)H_(11))2](m-Dy)were synthesized by using the isomeric dicarbollide ligands,namely[nido-7,8-C2BgH_(11)]^(2-)and[nido-7,9-C_(2)B_(9)H_(11)]^(2-).The structural details of o/m-Dy and m-Dy and magnetic dynamics of m-Dy were investigated to compare with the previous study on[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,2-C_(2)B_(9)H_(11))_(2)]o-Dy.The bending angles of sandwiched dysprosiacarboranes are straightened so as to improve energy bar-riers(U_(eff))from 430(5)to 591(0)K.Magneto-structural correlations show that the introduction of meta-C sites within the π-electron delocalized heterocyclic ring can effectively shorten the Dy-C_(2)B_(3)centroid distance and increase the C_(2)B_(3)centroid...Dy...C_(2)B_(3)centroid bending angle which is attributed to the dif-ferences in electronegativity between C and B atoms on the ring of C_(2)B_(3)^(2-).Therefore,to further enhance the performance of single-molecule magnets(SMMs)on this basis,future endeavors should focus on diminishing the equatorial solvent molecules to make a wider C2B3...Dy...C_(2)B_(3)bending angle.
基金supported by the National Natural Science Foundation of China(Nos.42074071,42274094,42261144739)the Shenzhen Science and Technology Program(No.KQTD20170810111725321)+2 种基金supported by the Taiwan University Core Consortiums Project(No.112L894202)the Higher Education Sprout Project of the Ministry of Education(No.112L901001)the National Science and Technology Council(No.111-2116-M-002-022-MY3)。
文摘The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China(Grant Nos.92365302,92065201,22325203,92265105,12074247,12174252,52102336)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grant Nos.2019SHZDZX01,19JC1412701,20QA1405100,24LZ1401000,LZPY2024-04)financial support from the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302500)。
文摘Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.
基金Project supported by the Fundamental Research Funds for the Provincial Universities of Zhejiang Province,China(Grant No.GK229909299001-05)Zhejiang Provincial Public Welfare Projects of China(Grant No.LGG22F030017)。
文摘The electronic structure,elasticity,and magnetic properties of the Mn_(2)XIn(X=Fe,Co)full-Heusler compounds are comprehensively investigated via first-principles calculations.The calculated elastic constants indicate that both Mn_(2)FeIn and Mn_(2)Co In possess ductility.At the optimal lattice constants,the magnetic moments are found to be 1.40μB/f.u.for Mn_(2)FeIn and 1.69μB/f.u.for Mn_(2)CoIn.Under the biaxial strain ranging from-2%to 5%,Mn_(2)FeIn demonstrates a remarkable variation in the spin polarization,spanning from-2%to 74%,positioning it as a promising candidate for applications in spintronic devices.Analysis of the electronic structure reveals that the change in spin polarization under strain is due to the shift of the spin-down states at the Fermi surface.Additionally,under biaxial strain,the magnetic anisotropy of Mn_(2)FeIn undergoes a transition of easy-axis direction.Utilizing second-order perturbation theory and electronic structure analysis,the variation in magnetic anisotropy with strain can be attributed to changes of d-orbital states near the Fermi surface.
基金supported by the National Key R&D Program of China(No.2021YFB3501204)the National Science Foundation for Excellent Young Scholars(No.52222107)+1 种基金the National Science Fund for Distinguished Young Scholars(No.51925605)the National Natural Science Foundation of China(No.52171195).
文摘Refrigeration in the liquid helium temperature range provides vital technological support for many scientific frontiers and engineering technologies.The considerable magnetocaloric effect(MCE)makes EuTiO_(3)a potential candidate for magnetic refrigeration near liquid helium temperature.More interestingly,the magnetic transition from antiferromagnetism to ferromagnetism offers the possibility to tailor the magnetism and improve the MCE of this magnetic system.In this study,the magnetic properties and MCE of EuTi_(0.875)Zr_(0.125)O_(3)were systematically investigated by first-principles calculation and experiments.The substitution of Zr induces a significant lattice expansion and alters the electronic interactions,leading to a dominance of ferromagnetism in the compound.Remarkable low-field MCE performance has been achieved attributed to the enhanced ferromagnetism and low saturation field.Under the field change of 0-1 T,the maximum magnetic entropy change(−△S_(M)^(max))and adiabatic temperature change(△T_(ad)^(max))are 17.9 J kg^(-1)K^(-1)and 6.1 K,respectively.It is worth noting that the−△S_(M)^(max)of EuTi_(0.875)Zr_(0.125)O_(3)reaches 10.3 J kg^(-1)K^(-1)for a field change of 0-0.5 T,making it one of the best magnetocaloric materials ever reported operating in the liquid helium temperature range.
基金Project supported by the National Key R&D Program of China (Grant Nos.2022YFA1403203 and 2021YFA1600201)the National Natural Science Foundation of China (Grant Nos.11974356 and 12274414)+1 种基金the Joint Funds of the National Natural Science Foundation of Chinathe Chinese Academy of Sciences Large-Scale Scientific Facility (Grant No.U1932216)。
文摘Group IV element Pb has been selected as the dopant to dope at the Sr site of Sr_(2)IrO_(4). It is exciting to find that the single-phase crystal structure could be maintained with a high Pb doping level of up to x=0.3 in Sr_(2-x)Pb_(x)IrO_(4). The mapping data obtained from energy-dispersive x-ray spectroscopy analyses give solid evidence that the Pb ions are uniformly distributed in the Sr_(2)IrO_(4) matrix. The incorporation of Pb leads to a moderate depression of the canted antiferromagnetic ordering state. The electrical conductivity could be greatly enhanced when the Pb doping content is higher than x=0.2.The present results give a fresh material base to explore new physics in doped Sr_(2)IrO_(4) systems.
基金the National Key Research and Development Program of China(Grant Nos.2022YFA1405100,2022YFA1403601,2020AAA0109005,and 2023YFB4502100)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang Province(Grant No.2022C01053)+1 种基金the National Natural Science Foundation of China(Grant Nos.12174405,12204497,12327806,and 62074063)Shenzhen Science and Technology Program(Grant No.JCYJ20220818103410022).
文摘Topological magnetism with strong robustness,nanoscale dimensions and ultralow driving current density(106 A/m^(2))is promising for applications in information sensing,storage,and processing,and thus sparking widespread research interest.Exploring candidate material systems with nanoscale size and easily tunable properties is a key for realizing practical topological magnetism-based spintronic devices.Here,we propose a class of ultrathin heterostructures,Fe/Bi_(2)O_(2)X(X=S,Se,Te)by deposing metal Fe on quasi-two-dimensional(2D)bismuth oxychalcogenides Bi_(2)O_(2)X(X=S,Se,Te)with excellent ferroelectric/ferroelastic properties.Large Dzyaloshinskii–Moriya interaction(DMI)and topological magnetism can be realized.Our atomistic spin dynamics simulations demonstrate that field-free vortex–antivortex loops and sub-10 nm skyrmions exist in Fe/Bi_(2)O_(2)S and Fe/Bi_(2)O_(2)Se interfaces,respectively.These results provide a possible strategy to tailor topological magnetism in ultrathin magnets/2D materials interfaces,which is extremely vital for spintronics applications.
基金Project supported by the Beijing Natural Science Foundation (Grant No. Z200005)the National Key R&D Program of China (Grant Nos. 2022YFA1403800 and 2023YFA1406500)+1 种基金the National Natural Science Foundation of China (Grant No. 12274459)Collaborative Research Project of Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology。
文摘We investigate the evolution of magnetic properties as well as the content and distribution of Mn for Mn(Sb_(1-x)Bi_(x))_(2)Te_(4) single crystals grown by large-temperature-gradient chemical vapor transport method.It is found that the ferromagnetic MnSb_(2)Te_(4) changes to antiferromagnetism with Bi doping when x≥0.25.Further analysis implies that the occupations of Mn ions at Sb/Bi site Mn_(Sb/Bi) and Mn site Mn_(Mn) have a strong influence on the magnetic ground states of these systems.With the decrease of Mn_(Mn) increase of Mn_(Sb/Bi),the system will favor the ferromagnetic ground state.In addition,the rapid decrease of T_(C/N) with increasing Bi content when x ≤0.25 and the insensitivity of T_(N) to x when x> 0.25 suggest that the main magnetic interaction may change from the Ruderman-Kittel-Kasuya-Yosida type at low Bi doping region to the van-Vleck type in high Bi doped samples.
基金supported by the National Science Foundation of China(Grant Nos.U1932215 and 12274186)the National Key Research and Development Program of China(Grant No.2022YFA1402704)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33010100)the Synergetic Extreme Condition User Facility(SECUF)。
文摘After the discovery of the ARECh_(2)(A=alkali or monovalent ions,RE=rare-earth,Ch=chalcogen)triangular lattice quantum spin liquid(QSL)family,a series of its oxide,sulfide,and selenide counterparts has been consistently reported and extensively investigated.While KErTe_(2) represents the initial synthesized telluride member,preserving its triangular spin lattice,it was anticipated that the substantial tellurium ions could impart more pronounced magnetic attributes and electronic structures to this material class.This study delves into the magnetism of KErTe_(2) at finite temperatures through magnetization and electron spin resonance(ESR)measurements.Based on the angular momentum J after spin-orbit coupling(SOC)and symmetry analysis,we obtain the magnetic effective Hamiltonian to describe the magnetism of Er^(3+)in R3m space group.Applying the mean-field approximation to the Hamiltonian,we can simulate the magnetization and magnetic heat capacity of KErTe_(2) in paramagnetic state and determine the crystalline electric field(CEF)parameters and partial exchange interactions.The relatively narrow energy gaps between the CEF ground state and excited states exert a significant influence on the magnetism.For example,small CEF excitations can result in a significant broadening of the ESR linewidth at 2 K.For the fitted exchange interactions,although the values are small,given a large angular momentum J=15/2 after SOC,they still have a noticeable effect at finite temperatures.Notably,the heat capacity data under different magnetic fields along the𝑐axis direction also roughly match our calculated results,further validating the reliability of our analytical approach.These derived parameters serve as crucial tools for future investigations into the ground state magnetism of KErTe_(2).The findings presented herein lay a foundation for exploration of the intricate magnetism within the triangular-lattice delafossite family.
基金supported by the National Natural Science Foundation of China(NSFC,No.22101091)the Fundamental Research Funds for the Central Universities(No.2019kfyXKJC016)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B210003),Knowledge Innovation Program of Wuhan-Basic Research.
文摘Functional materials with multiple properties are urgent to be explored to reach high requirements for applications nowadays.In this work,a new multifunctional one-dimensional(1D)chain compound[N(C_(3)H_(7))_(4)][Cu(ohpma)]·H_(2)O 1(ohpma=deprotonated N-(2-hydoxyphenyl)oxamic acid)exhibiting both 1D antiferromagnetic and nonlinear optical properties,which are both originated from the same polar[Cu(C_(8)H_(4)NO_(4))]magnetic units,has been successfully synthesized by evaporation at room temperature.Bis-polydentate nature of the(ohpma)3−ligand with constrained tridentate and bidentate coordination sites conducts Cu^(2+)ions coordinating in different geometries and forms 1D chains along the c axis,which are further separated by the[N(C_(3)H_(7))_(4)]+cations.And the 1D magnetic chains further exhibit noncentrosymmetric polar arrangement.Nonlinear optical study shows polar compound 1 exhibits a discernible second-harmonic generation(SHG)efficiency and the calculation of the partial density of states indicates that the SHG efficiency of 1 is mainly originated from the polar[Cu(C_(8)H_(4)NO_(4))]magnetic units.Moreover,magnetic susceptibility shows a broad maximum around 70 K with strong intrachain interaction of J/k B=−113.0 K but no long-range order is observed down to 2 K,suggesting that 1 shows a good 1D magnetism.Both good 1D magnetism and SHG activity suggest that 1 could be as a potential multifunctional material,particularly.
