The Agadem block is an area of major oil interest located in the large sedimentary basin of Termit,in the south-east of the Republic of Niger.Since the 1950s,this basin has known geological and geophysical research ac...The Agadem block is an area of major oil interest located in the large sedimentary basin of Termit,in the south-east of the Republic of Niger.Since the 1950s,this basin has known geological and geophysical research activities.However,despite the extensive research carried out,we believe that a geophysical contribution in terms of magnetic properties and their repercussions on the structure of the Agadem block allowing the improvement of existing knowledge is essential.The present study aims to study the structural characteristics of the Agadem block associated with magnetic anomalies.For this,after data shaping,several filtering techniques were applied to the aeromagnetic data to identify and map deep geological structures.The reduction to the pole map shows large negative wavelength anomalies in the southeast half of the block and short positive wavelength anomalies in the northwest part embedded in a large positive anomaly occupying the lower northern half of the block.The maps of the total horizontal derivative and tilt angle show lineaments globally distributed along the NW-SE direction in accordance with the structural style of the study area.The resulting map highlights numerous lineaments that may be associated with faults hidden by the sedimentary cover.The calculation of the Euler deconvolution allowed us to locate and estimate the depths of magnetic sources at variable depths of up to 4000 m.The compilation of the results obtained allowed us to locate zones of high and low intensities which correspond respectively to horsts and grabens as major structures of the Agadem block.展开更多
This paper provides an overview of the recent advancements in magnetic structured triboelectric nanogenerators(MSTENGs)and their potential for energy harvesting and sensing in coastal bridge infrastructure.This paper ...This paper provides an overview of the recent advancements in magnetic structured triboelectric nanogenerators(MSTENGs)and their potential for energy harvesting and sensing in coastal bridge infrastructure.This paper begins with a brief discussion on the fundamental physics modes of triboelectric nanogenerators(TENGs),triboelectric series,and factors affecting TENG power generation and transmission,providing a foundation for the subsequent sections.The review focuses on the different types of MSTENGs and their applications in coastal infrastructure.Specifically,it covers magnetic spherical TENG networks,magnet-assisted TENGs,MSTENGs for bridges,and magnetic multilayer structures based on TENGs.The advantages and limitations of each type of MSTENG are discussed in detail,highlighting their respective suitability for different coastal bridge infrastructure applications.In addition,the paper addresses the challenges and provides insights into the future of MSTENGs.These include the need for improved durability and sustainability of MSTENGs in harsh coastal environments,increasing their power-output levels to fulfll high energy needs,and the requirement for collaborative efforts between academia,industry,and government institutions to optimize MSTENG performance.展开更多
Understanding the continental margin of the Northeastern South China Sea is critical to the study of deep structures, tectonic evolution, and dynamics of the region. One set of important data for this endeavor is the ...Understanding the continental margin of the Northeastern South China Sea is critical to the study of deep structures, tectonic evolution, and dynamics of the region. One set of important data for this endeavor is the total-field magnetic data. Given the challenges associated with the magnetic data at low latitudes and with remanent magnetism in this area, we combine the equivalent-source technique and magnetic amplitude inversion to recover 3D subsurface magnetic structures. The inversion results show that this area is characterized by a north-south block division and east-west zonation. Magnetic regions strike in EW, NE and NW direction and are consistent with major tectonic trends in the region. The highly magnetic zone recovered from inversion in the continental margin differs visibly from that of the magnetically quiet zones to the south. The magnetic anomaly zone strikes in NE direction, covering an area of about 500 km × 60 km, and extending downward to a depth of 25 km or more. In combination with other geophysical data, we suggest that this strongly magnetic zone was produced by deep underplating of magma associated with plate subduction in Mesozoic period. The magnetically quiet zone in the south is an EW trending unit underlain by broad and gentle magnetic layers of lower crust. Its magnetic structure bears a clear resemblance to oceanic crust, assumed to be related to the presence of ancient oceanic crust there.展开更多
M-T curves, M-H curves and electron spin resonance (ESR) curves of LaMn_(1-x)Zn_xO_3(x=0.05, 0.10, (0.20,) 0.30, 0.40) were studied. Experimental results indicate that: with increasing Zn doping, the T_C value decreas...M-T curves, M-H curves and electron spin resonance (ESR) curves of LaMn_(1-x)Zn_xO_3(x=0.05, 0.10, (0.20,) 0.30, 0.40) were studied. Experimental results indicate that: with increasing Zn doping, the T_C value decreases monotonously, and the system undergoes a transition from long-range ferromagnetic order to cluster-spin glass stated. The results are attributed to double exchange interaction, magnetic dilution and lattice effects by Zn doping.展开更多
The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4....The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.展开更多
We report the physical properties, crystalline and magnetic structures of singe crystals of a new layered antiferromagnetic(AFM) material PrPd0.82Bi2. The measurements of magnetic properties and heat capacity indicate...We report the physical properties, crystalline and magnetic structures of singe crystals of a new layered antiferromagnetic(AFM) material PrPd0.82Bi2. The measurements of magnetic properties and heat capacity indicate an AFM phase transition at TN^7K. A large Sommerfeld coefficient of 329.23 m J·mol-1·K-2 is estimated based on the heat capacity data, implying a possible heavy-fermion behavior. The magnetic structure of this compound is investigated by a combined study of neutron powder and single-crystal diffraction. It is found that an A-type AFM structure with magnetic propagation wavevector k =(0 0 0) is formed below TN. The Pr3+ magnetic moment is aligned along the crystallographic c-axis with an ordered moment of 1.694(3) μBat 4K, which is smaller than the effective moment of the free Pr3+ ion of 3.58 μB.PrPd0.82Bi2 can be grown as large as 1 mm×1 cm in area with a layered shape, and is very easy to be cleaved, providing a unique opportunity to study the interplay between magnetism, possible heavy fermions, and superconductivity.展开更多
Magnetic structure of the continental crust is one of the important geophysical aspects of continental lithosphere. This paper reviews the achievements in the research into the magnetic structure and its significance ...Magnetic structure of the continental crust is one of the important geophysical aspects of continental lithosphere. This paper reviews the achievements in the research into the magnetic structure and its significance for crustal tectonics, composition, metamorphic facies, crust mantle interaction and magnetization of deep crust. Further studies are suggested according to the basic principles of rock and mineral magnetism in terms of petrology, geochemistry and structural geology. Emphasis is placed on new geological ideas and synthetic studies of the relationship between deep geological processes and interpretation of gravity, magnetic, electrical and seismic data. The relationships between magnetic, density, electricity, velocity, geothermal structures and deep geodynamic processes are taken as a system for the research into the deep geology.展开更多
The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic...The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic moment 0.772（6） μB at 10 K pointing in the basal plane couples ferromagnetically in the plane, which stacks antiferromagnetically along the c direction. Tuning and suppressing the interplane antiferromagnetic interaction may be crucial to induce a superconducting state in the material.展开更多
Based on the multipoint magnetic observations of Cluster from 2001 to 2004,the magnetic field structure in magnetotail Neutral Sheet(NS) is statistically surveyed.The results are as follows.In NS,a cubic function is s...Based on the multipoint magnetic observations of Cluster from 2001 to 2004,the magnetic field structure in magnetotail Neutral Sheet(NS) is statistically surveyed.The results are as follows.In NS,a cubic function is selected to reveal the relation between y(GSM) and positional parameter z.The relation between y and magnetic field values indicates that the magnetic field is weak at midnight region and strengthens gradually at the duskside and dawnside.The relation between y and curvature radius is expressed by a quadratic function.And R_c of flattened CS is less than that of the normal CS.B_y determines the orientation of MFLs' configuration.The polar angle of the curvature vector is affected by the NS configuration.In addition,the correlation between the polar angle of the curvature vector and z is higher.The polar angle of the normal of the osculating plane is uncertain in the center area.The relation between the azimuthal angles of the curvature vector(the normal of the osculating plane) and y is negatively correlated.An empirical model applied to yz plane of the three-dimensional structure of the magnetic field lines in the NS are developed,and it is represented as a function of the positional parameter y.Finally,the current density is also statistically surveyed.展开更多
The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabili...The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabilized magnetic structure evolves with increasing hole doping level.Namely,the stripe antiferromagnetic phase dominates at zero doping,while magnetic structures with more antiferromagnetic linking numbers such as the staggered tetramer,staggered trimer,and staggered dimer phases become energetically favorable as the hole density increases.At a certain doping level,energy degeneracy of different magnetic structures appears,indicating strong magnetic frustration and magnetic fluctuations in the system.We suggest that the magnetic competition induced by the hole doping may explain the fast decrease of the Neel temperature TNand the moderately suppressed magnetic moment in the hole doped Fe-pnicitides.Moreover,our results show a sign reversal of the kinetic energy anisotropy as the magnetic ground state evolves,which may be the mechanism behind the puzzling sign reversal of the in-plane resistivity anisotropy in hole-doped Fe-pnicitides.展开更多
Owing to the strong neutron absorption of 151Eu,151Eu free 153EuMnO3-δhas been synthesized to collect the neutron diffraction data for analyzing the magnetic structure of EuMnO3-δ.The obtained neutron diffraction da...Owing to the strong neutron absorption of 151Eu,151Eu free 153EuMnO3-δhas been synthesized to collect the neutron diffraction data for analyzing the magnetic structure of EuMnO3-δ.The obtained neutron diffraction data of 153EuMnO3-δindicates that the magnetic diffraction peaks corresponding to cAAFM(canted A-type antiferromagnetic)phase can be observed,but the magnetic diffraction peaks corresponding to expected ICAFM(incommensurate antiferromagnetic)phase may be too weak to be observed.展开更多
The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challengin...The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.展开更多
The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new mate...The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new material is extruded,the crust spreads outward,retaining its magnetization.The reversal of the polarity of the Earth's magnetic field over geologic time leads to a pattern of striped magnetic anomalies.In this study,we carry out a preliminary evaluation on how data from the Macao Science Satellite-1(MSS-1),which has a low orbital inclination,influences inversion models of the oceanic crustal magnetic field when combined with data from the Swarm mission.For our modeling we use an equivalent source method based on a cubed-sphere grid.Our model captures the broad magnetic structure over the North Atlantic Ocean and demonstrates that the trend of magnetic stripes is consistent with the age frame of the oceanic crust.The amplitude of the radial magnetic field at 450 km the North Atlantic Ocean ranges from–11 nT to+8 nT.The addition of MSS-1 observations to Swarm data generates results consistent with the overall magnetic stripe pattern.The lack of short-wavelength scale structure reveals the limitation of high-altitude satellites in portraying fine features and hence lower-altitude observations would be required to delineate a more detailed crustal signature.It is expected to obtain a finer structure of oceanic magnetic stripes by combining low-altitude CHAMP field data and east-west gradient data derived from MSS-1 in future work.展开更多
In order to calculate the multipoles in real materials with considerable intersite Coulomb interaction V,we develop a self-consistent program which starts from the frst-principles calculations to solve the tight-bindi...In order to calculate the multipoles in real materials with considerable intersite Coulomb interaction V,we develop a self-consistent program which starts from the frst-principles calculations to solve the tight-binding Hamiltonian including onsite Coulomb repulsion U,V,and spin-orbital couplingλ.The program is applied to Ba_(2)MgReO_(6)to fgure out the mechanism of structural instability and magnetic ordering.A comprehensive quadrupole phase diagram versus U and V withλ=0.28 eV is calculated.Our results demonstrate that the easy-plane anisotropy and the intersite Coulomb repulsion V must be considered to remove the orbital frustration.The increase of V to>20 meV would arrange quadrupole Q_(x^(2)-y^(2))antiparallelly,accompanied by small parallel Q_(3z)^(2)-r^(2),and stabilize Ba_(2)MgReO_(6)into the body-centered tetragonal structure.Such antiparallel Q_(x^(2)-y^(2))provides a new mechanism for the Dzyaloshinskii-Moriya interaction and gives rise to the canted antiferromagnetic(CAF)state along the[110]axis.Moreover,sizable octupoles such as O_(21)^(31),O_(21)^(33),O_(21)^(34)and O_(21)^(36)are discovered for the frst time in the CAF state.Our study not only provides a comprehensive understanding of the experimental results in Ba_(2)MgReO_(6),but also serves as a general and useful tool for the study of multipole physics in 5d compounds.展开更多
Densities and various magnetic parameters (susceptibility, saturation magnetization, saturation isothermal remanent magnetization and intrinsic coercivity) were measured for 20 representative rock samples of different...Densities and various magnetic parameters (susceptibility, saturation magnetization, saturation isothermal remanent magnetization and intrinsic coercivity) were measured for 20 representative rock samples of different lithologies from the Archean Kongling amphibolite to granulite facies terrain of the Yangtze craton. Metasedimentary rocks and tonalitic trondhjemitic granodioritic granitic (TTGG) gneisses show that values of susceptibility κ and saturation isothermal remanent magnetization SIRM are higher than those of amphibolites and gabbros. The felsic gneisses have averages of κ =(1 163±375)×10 -6 SI, SIRM =(18.23±8.38) A/m and R 1=0.083 3± 0.005 7 and the metasedimentary rocks κ =(1 236±823)×10 -6 SI, SIRM =(20.70±10.91) A/m and R I=0.071 4±0.025 2. In contrast, mafic rocks have average κ =(764±316)×10 -6 SI, SIRM = (10.46±3.94)A/m and R 1=0.036±0.009 4, and are dominated by a mixed paramagnetic and ferrimagnetic behavior. Thermal magnetic analyses indicate that magnetite and maghemite of low coercivity are the major carriers of remanent magnetism in the metaclastic sedimentary rocks and TTGG gneisses. The amphibolite and gabbro contain minor amounts of magnetite and pyrrhotite. Magnetism of metaclastic sedimentary rocks and TTGG gneisses is highly heterogeneous; variation coefficients of κ and SIRM are as high as 67 % and 53 % for the former and 32 % and 46 % for the latter. Mineral compositions suggest that biotite may be responsible for the higher magnetism of the metasedimentary rocks. The highest variations in κ, SIRM and R I exhibited by metasedimentary rocks can also be interpreted by their largest absolute variations in biotite mass fraction relative to mafic rocks and felsic gneisses. The average ratio ( Q ) of natural remanent magnetization to induced magnetization of felsic gneisses and metasediments is 0.47 . Ratios ( REM ) of natural remanent to saturation isothermal remanent magnetization ranges between 0.000 001 and 0.027 000 and averages 0.002 540. These values are comparable to those of rocks of similar lithologies from the Archean Taihua high grade terrain of the North China craton and from the Ivrea zone, northern Italy. The dominant phase of magnetism carried by the Kongling rocks is suggested to be thermal remanent magnetization. Consequently, high temperature metamorphism exceeding the Curie point of magnetite (585 ℃) might be responsible for the formation of rock magnetism of the exposed crust in the area of investigation.展开更多
Magnetic neutron scattering in Y-type hexagonal ferrite crystals, studied by the author in 1968-1971 and presented in the article showed that the entire density of the so-called magnetic moments of Fe<span style=&q...Magnetic neutron scattering in Y-type hexagonal ferrite crystals, studied by the author in 1968-1971 and presented in the article showed that the entire density of the so-called magnetic moments of Fe<span style="white-space:nowrap;"><sup>3+</sup></span> ions can significantly shift from the position of their nuclei. As result of these shift the structure in form of the chain magnetic spiral is realized in ferrite lattice. The noted shifts of the “magnetic moments” served as the basis for the author’s assumption that these “moments” are “fig sheets” behind which the magnetic poles (magnetic charges) real existing in the shells of atoms are hidden. In this case, the scattering of neutrons is carried out by magnetic charges, and not theoretical surrogates in the form of magnetic moments. In addition to participating in atomic structures, magnetic charges populate potential conduction zones in conductors, where they are exist in compositions of magnetic dipoles. Under the influence of an external magnetic field, a polarization of magnetic dipoles is realized in the conductor, the field strengths of which are directed against the external magnetic field. It is these dipole magnetic fields that are responsible for such a well-known physical phenomenon as diamagnetism. Under the conditions of noted polarization of magnetic dipoles the author managed to perform mechanical separation of magnetic charges in pairs ±g and to charge experienced bodies (metal plates) by the magnetic charges of one sign. The fact of such a charging was detected through magnetostatic interaction between magnetic charges on the plates using highly sensitive torsion balances. This experiment is presented in detail in this article. The results of these experiments, as well as subsequent experimental and theoretical studies of the author, which, in general composition, were carried out from 1968 to the present, showed that magnetic charges are real structural components of the atoms and substance. So, for example, the atomic shells are not electronic but electromagnetic. The main reason that real magnetic charges were <span style="font-family:Verdana;">“</span><span style="font-family:Verdana;">buried alive” in the existing physical theories is the physics of their confinement in substance forces of which, in its rigidity, is many times greater than the electron confinement forces.</span>展开更多
Magnetic structure of Pr6Fe13Ge at room temperature has been investigated by magnetic measurement, Mossbauer effect and neutron diffraction. Magnetic atoms are closely packed up and down the mirror planes at z = 0 and...Magnetic structure of Pr6Fe13Ge at room temperature has been investigated by magnetic measurement, Mossbauer effect and neutron diffraction. Magnetic atoms are closely packed up and down the mirror planes at z = 0 and 1/2 and separated by the non-magnetic atoms located on the planes at z= 1/4 and 3/4, which constructs an M/NM/M sandwich structure (M: magnetic, NM: non-magnetic). The intralayer magnetic moments couple ferromagnetically and are out of ab plane at a small angle so as to form a component along c-axis. The interlayer coupling is antiferromagnetic for the ab component while ferromagnetic for the c component.展开更多
We examine the electronic and magnetic structures of iron telluride KFe2Te2 using first-principle calculations. We demonstrate that the ground state of this compound is in bicollinear antiferromag- netic order with Fe...We examine the electronic and magnetic structures of iron telluride KFe2Te2 using first-principle calculations. We demonstrate that the ground state of this compound is in bicollinear antiferromag- netic order with Fe local moments （- 2.6 μB） that are ferromagnetically aligned along a diagonal direction and antiferromagnetically aligned along the other diagonal in the Fe-Fe square lattice, sim- ilar to the alignment discovered in the parent compound of superconductor α-FeTe. This bicollinear antiferromagnetic order results from the interplay among the nearest, next-nearest, and next-next- nearest neighbor exchange interactions, which are mediated by Te 5p orbitals. This finding may aid our understanding of the interplay between magnetism and superconductivity in the family of iron-based materials.展开更多
The bulk photovoltaic effect(BPVE)is a second-order optical process in noncentrosymmetric materials that converts the light into DC currents.BPVE is classified into shift current and injection current according to the...The bulk photovoltaic effect(BPVE)is a second-order optical process in noncentrosymmetric materials that converts the light into DC currents.BPVE is classified into shift current and injection current according to the generation mechanisms and their dependence on the polarization of light is sensitive to the spatial and time-reversal symmetry of materials.In this work,we present a comprehensive study on the BPVE response of EuSn_(2)As_(2) with different magnetic structures through symmetry analysis and first-principles calculation.We demonstrate that the interlayer antiferromagnetic(AFM)EuSn_(2)As_(2) of even-layer breaks the inversion symmetry and has the second-order optical responses.Moreover,the bilayer AFM EuSn_(2)As_(2) not only displays distinct BPVE responses when magnetic moments align in different directions,but also shows symmetry-related responses in two phases which have mutually perpendicular in-plane magnetic moments.Due to the dependence of BPVE responses on the polarization of light and magnetic symmetry,these magnetic structures can be distinguished by the circular polarized light with well-designed experiments.Our work demonstrates the feasibility of the BPVE response as a tool to probe the magnetic structure.展开更多
Electromagnetic interference(EMI)shielding materials with ultrathin,flexible,superior mechanical and thermal management properties are highly desirable for smart and wearable electronics.Here,ultrathin and flexible Ni...Electromagnetic interference(EMI)shielding materials with ultrathin,flexible,superior mechanical and thermal management properties are highly desirable for smart and wearable electronics.Here,ultrathin and flexible Ni/Cu/metallic glass/Cu/Ni(Ni/Cu/MG)multilayer composite with alternate magnetic and electrical structures was designed via facial electroless plating of Cu and Ni on an Fe-based metallic glass.The resultant 0.02 mm-thick Ni/Cu/MG composite displays a superior EMI shielding effectiveness(EMI SE)of 35 dB and a great EMI SE/t of 1750 dB/mm,which is greater than those of composites with monotonous multilayer or homogeneous structures.The improved EMI SE originates from the massive ohmic losses,the enhanced internal reflection/absorption,and the abundant interfacial polarization loss.Particularly,Ni/Cu/MG exhibits a high tensile strength of up to 1.2 GPa and outstanding mechanical stability,enabling the EMI SE remains unchanged after 10,000 times of bending.Moreover,Ni/Cu/MG has excellent Joule heating characteristics and thermal stability,which is very suitable for heating components of wearable hyperthermia devices.展开更多
文摘The Agadem block is an area of major oil interest located in the large sedimentary basin of Termit,in the south-east of the Republic of Niger.Since the 1950s,this basin has known geological and geophysical research activities.However,despite the extensive research carried out,we believe that a geophysical contribution in terms of magnetic properties and their repercussions on the structure of the Agadem block allowing the improvement of existing knowledge is essential.The present study aims to study the structural characteristics of the Agadem block associated with magnetic anomalies.For this,after data shaping,several filtering techniques were applied to the aeromagnetic data to identify and map deep geological structures.The reduction to the pole map shows large negative wavelength anomalies in the southeast half of the block and short positive wavelength anomalies in the northwest part embedded in a large positive anomaly occupying the lower northern half of the block.The maps of the total horizontal derivative and tilt angle show lineaments globally distributed along the NW-SE direction in accordance with the structural style of the study area.The resulting map highlights numerous lineaments that may be associated with faults hidden by the sedimentary cover.The calculation of the Euler deconvolution allowed us to locate and estimate the depths of magnetic sources at variable depths of up to 4000 m.The compilation of the results obtained allowed us to locate zones of high and low intensities which correspond respectively to horsts and grabens as major structures of the Agadem block.
文摘This paper provides an overview of the recent advancements in magnetic structured triboelectric nanogenerators(MSTENGs)and their potential for energy harvesting and sensing in coastal bridge infrastructure.This paper begins with a brief discussion on the fundamental physics modes of triboelectric nanogenerators(TENGs),triboelectric series,and factors affecting TENG power generation and transmission,providing a foundation for the subsequent sections.The review focuses on the different types of MSTENGs and their applications in coastal infrastructure.Specifically,it covers magnetic spherical TENG networks,magnet-assisted TENGs,MSTENGs for bridges,and magnetic multilayer structures based on TENGs.The advantages and limitations of each type of MSTENG are discussed in detail,highlighting their respective suitability for different coastal bridge infrastructure applications.In addition,the paper addresses the challenges and provides insights into the future of MSTENGs.These include the need for improved durability and sustainability of MSTENGs in harsh coastal environments,increasing their power-output levels to fulfll high energy needs,and the requirement for collaborative efforts between academia,industry,and government institutions to optimize MSTENG performance.
基金supported by the Chinese Scholarship Foundation,the Gravity and Magnetics Research Consortium(GMRC)the National Natural Science Foundation of China(No.41074095)+1 种基金the National Special Project(No.201011039)the Open Project of the National Key Laboratory for Geological Processes and Mineral Resources(No.GPMR0942)
文摘Understanding the continental margin of the Northeastern South China Sea is critical to the study of deep structures, tectonic evolution, and dynamics of the region. One set of important data for this endeavor is the total-field magnetic data. Given the challenges associated with the magnetic data at low latitudes and with remanent magnetism in this area, we combine the equivalent-source technique and magnetic amplitude inversion to recover 3D subsurface magnetic structures. The inversion results show that this area is characterized by a north-south block division and east-west zonation. Magnetic regions strike in EW, NE and NW direction and are consistent with major tectonic trends in the region. The highly magnetic zone recovered from inversion in the continental margin differs visibly from that of the magnetically quiet zones to the south. The magnetic anomaly zone strikes in NE direction, covering an area of about 500 km × 60 km, and extending downward to a depth of 25 km or more. In combination with other geophysical data, we suggest that this strongly magnetic zone was produced by deep underplating of magma associated with plate subduction in Mesozoic period. The magnetically quiet zone in the south is an EW trending unit underlain by broad and gentle magnetic layers of lower crust. Its magnetic structure bears a clear resemblance to oceanic crust, assumed to be related to the presence of ancient oceanic crust there.
文摘M-T curves, M-H curves and electron spin resonance (ESR) curves of LaMn_(1-x)Zn_xO_3(x=0.05, 0.10, (0.20,) 0.30, 0.40) were studied. Experimental results indicate that: with increasing Zn doping, the T_C value decreases monotonously, and the system undergoes a transition from long-range ferromagnetic order to cluster-spin glass stated. The results are attributed to double exchange interaction, magnetic dilution and lattice effects by Zn doping.
基金Supported by the National Basic Research Program of China under Grant Nos 2012CB921700 and 2011CBA00112the National Natural Science Foundation of China under Grant Nos 11034012 and 11190024
文摘The magnetic structure of the spin-chain antiferromagnet SrCo2 V208 is determined by single-crystal neutron diffraction experiment. The system undergoes a long-range magnetic order below the critical temperature TN=4.96 K. The moment of 2.16#B per Co at 1.6K in the screw chain running along the c axis Mternates in the c axis. The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetieally Monk the other in-plane axis. This magnetic configuration breaks the four-fold symmetry of the tetragonM crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis. The very similar magnetic state to the isostructural BaCo2 V~ 08 warrants SrCo2 V2 08 as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.
基金National Key Research and Development Program of China(Grant Nos.2017YFA0302901 and 2016YFA0300604)the National Natural Science Foundation of China(Grant No.11774399)+2 种基金Beijing Natural Science Foundation,China(Grant No.Z180008)the K.C.Wong Education Foundation(Grant No.GJTD-2018-01)the DAAD-PPP programme,and the joint German-Sino HGF-OCPC Postdoc Programme.
文摘We report the physical properties, crystalline and magnetic structures of singe crystals of a new layered antiferromagnetic(AFM) material PrPd0.82Bi2. The measurements of magnetic properties and heat capacity indicate an AFM phase transition at TN^7K. A large Sommerfeld coefficient of 329.23 m J·mol-1·K-2 is estimated based on the heat capacity data, implying a possible heavy-fermion behavior. The magnetic structure of this compound is investigated by a combined study of neutron powder and single-crystal diffraction. It is found that an A-type AFM structure with magnetic propagation wavevector k =(0 0 0) is formed below TN. The Pr3+ magnetic moment is aligned along the crystallographic c-axis with an ordered moment of 1.694(3) μBat 4K, which is smaller than the effective moment of the free Pr3+ ion of 3.58 μB.PrPd0.82Bi2 can be grown as large as 1 mm×1 cm in area with a layered shape, and is very easy to be cleaved, providing a unique opportunity to study the interplay between magnetism, possible heavy fermions, and superconductivity.
基金This study is supported by the Visiting Scholar Foundation of Key Lab in University of Chinathe Ministry of Education and the
文摘Magnetic structure of the continental crust is one of the important geophysical aspects of continental lithosphere. This paper reviews the achievements in the research into the magnetic structure and its significance for crustal tectonics, composition, metamorphic facies, crust mantle interaction and magnetization of deep crust. Further studies are suggested according to the basic principles of rock and mineral magnetism in terms of petrology, geochemistry and structural geology. Emphasis is placed on new geological ideas and synthetic studies of the relationship between deep geological processes and interpretation of gravity, magnetic, electrical and seismic data. The relationships between magnetic, density, electricity, velocity, geothermal structures and deep geodynamic processes are taken as a system for the research into the deep geology.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921700)the National Natural Science Foundation of China(Grant No.11190024)+2 种基金the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Renmin University of China(Grant Nos.17XNLF04 and 17XNLF06)support from China Scholarship Council
文摘The magnetic structure of CsCo_2 Se_2 was investigated using single-crystal neutron diffraction technique. An antiferromagnetic transition with the propagation vector（0,0,1） was observed at TN= 78 K. The Co magnetic moment 0.772（6） μB at 10 K pointing in the basal plane couples ferromagnetically in the plane, which stacks antiferromagnetically along the c direction. Tuning and suppressing the interplane antiferromagnetic interaction may be crucial to induce a superconducting state in the material.
基金Supported by the National Natural Science Foundation of China(41231066)Ministry of Science and Technology of China(2011CB811404)+1 种基金the Specialized Research Fund for State Key Laboratories of the CASthe Scientific Research Staring Foundation for Nanjing University of Information Science and Technology(2013x030)
文摘Based on the multipoint magnetic observations of Cluster from 2001 to 2004,the magnetic field structure in magnetotail Neutral Sheet(NS) is statistically surveyed.The results are as follows.In NS,a cubic function is selected to reveal the relation between y(GSM) and positional parameter z.The relation between y and magnetic field values indicates that the magnetic field is weak at midnight region and strengthens gradually at the duskside and dawnside.The relation between y and curvature radius is expressed by a quadratic function.And R_c of flattened CS is less than that of the normal CS.B_y determines the orientation of MFLs' configuration.The polar angle of the curvature vector is affected by the NS configuration.In addition,the correlation between the polar angle of the curvature vector and z is higher.The polar angle of the normal of the osculating plane is uncertain in the center area.The relation between the azimuthal angles of the curvature vector(the normal of the osculating plane) and y is negatively correlated.An empirical model applied to yz plane of the three-dimensional structure of the magnetic field lines in the NS are developed,and it is represented as a function of the positional parameter y.Finally,the current density is also statistically surveyed.
基金the Guangxi Natural Science Foundation,China(Grant Nos.2022GXNSFAA035560and GuikeAD20159009)the Scientific Research Foundation of Guilin University of Technology(Grant No.GLUTQD2017009)。
文摘The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabilized magnetic structure evolves with increasing hole doping level.Namely,the stripe antiferromagnetic phase dominates at zero doping,while magnetic structures with more antiferromagnetic linking numbers such as the staggered tetramer,staggered trimer,and staggered dimer phases become energetically favorable as the hole density increases.At a certain doping level,energy degeneracy of different magnetic structures appears,indicating strong magnetic frustration and magnetic fluctuations in the system.We suggest that the magnetic competition induced by the hole doping may explain the fast decrease of the Neel temperature TNand the moderately suppressed magnetic moment in the hole doped Fe-pnicitides.Moreover,our results show a sign reversal of the kinetic energy anisotropy as the magnetic ground state evolves,which may be the mechanism behind the puzzling sign reversal of the in-plane resistivity anisotropy in hole-doped Fe-pnicitides.
基金This work is supported by the National Natural Science Foundation of China(Grant 21771007).
文摘Owing to the strong neutron absorption of 151Eu,151Eu free 153EuMnO3-δhas been synthesized to collect the neutron diffraction data for analyzing the magnetic structure of EuMnO3-δ.The obtained neutron diffraction data of 153EuMnO3-δindicates that the magnetic diffraction peaks corresponding to cAAFM(canted A-type antiferromagnetic)phase can be observed,but the magnetic diffraction peaks corresponding to expected ICAFM(incommensurate antiferromagnetic)phase may be too weak to be observed.
基金supported by the National Natural Science Foundation of China[Grant Nos.52272288 and 51972039]the China Postdoctoral Science Foundation[No.2021M700658].
文摘The construction of carbon nanocoil(CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption.However,it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms.Herein,the chiral CNCs are first synthesized on a threedimensional(3D)carbon foam and then combined with the FeNi/NiFe_(2)O_(4) nanoparticles to form a novel chiral-dielectric-magnetic trinity foam.The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss.The formation of the FeNi-carbon interfaces induces interfacial polarization loss,which is confirmed by the density functional theory calculations.Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects,which enhance the magnetic anisotropy and magnetic loss capability.Owing to the synergistic effect between dielectricity,chirality,and magnetism,the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth(EAB)of 14 GHz and a minimum reflection of loss less than-50 dB.More importantly,the C-band EAB of the foam is extended to 4 GHz,achieving the full C-band coverage.This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.
基金supported by the National Natural Science Foundation of China(42250101,42250102,42250103)the Macao Foundation,and the Science and Technology Development Fund,Macao SAR(File No.0002/2019/APD)。
文摘The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new material is extruded,the crust spreads outward,retaining its magnetization.The reversal of the polarity of the Earth's magnetic field over geologic time leads to a pattern of striped magnetic anomalies.In this study,we carry out a preliminary evaluation on how data from the Macao Science Satellite-1(MSS-1),which has a low orbital inclination,influences inversion models of the oceanic crustal magnetic field when combined with data from the Swarm mission.For our modeling we use an equivalent source method based on a cubed-sphere grid.Our model captures the broad magnetic structure over the North Atlantic Ocean and demonstrates that the trend of magnetic stripes is consistent with the age frame of the oceanic crust.The amplitude of the radial magnetic field at 450 km the North Atlantic Ocean ranges from–11 nT to+8 nT.The addition of MSS-1 observations to Swarm data generates results consistent with the overall magnetic stripe pattern.The lack of short-wavelength scale structure reveals the limitation of high-altitude satellites in portraying fine features and hence lower-altitude observations would be required to delineate a more detailed crustal signature.It is expected to obtain a finer structure of oceanic magnetic stripes by combining low-altitude CHAMP field data and east-west gradient data derived from MSS-1 in future work.
基金was supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1611200 and 2018YFA0307000)the National Natural Science Foundation of China(Grant Nos.12274154 and 12404182)。
文摘In order to calculate the multipoles in real materials with considerable intersite Coulomb interaction V,we develop a self-consistent program which starts from the frst-principles calculations to solve the tight-binding Hamiltonian including onsite Coulomb repulsion U,V,and spin-orbital couplingλ.The program is applied to Ba_(2)MgReO_(6)to fgure out the mechanism of structural instability and magnetic ordering.A comprehensive quadrupole phase diagram versus U and V withλ=0.28 eV is calculated.Our results demonstrate that the easy-plane anisotropy and the intersite Coulomb repulsion V must be considered to remove the orbital frustration.The increase of V to>20 meV would arrange quadrupole Q_(x^(2)-y^(2))antiparallelly,accompanied by small parallel Q_(3z)^(2)-r^(2),and stabilize Ba_(2)MgReO_(6)into the body-centered tetragonal structure.Such antiparallel Q_(x^(2)-y^(2))provides a new mechanism for the Dzyaloshinskii-Moriya interaction and gives rise to the canted antiferromagnetic(CAF)state along the[110]axis.Moreover,sizable octupoles such as O_(21)^(31),O_(21)^(33),O_(21)^(34)and O_(21)^(36)are discovered for the frst time in the CAF state.Our study not only provides a comprehensive understanding of the experimental results in Ba_(2)MgReO_(6),but also serves as a general and useful tool for the study of multipole physics in 5d compounds.
文摘Densities and various magnetic parameters (susceptibility, saturation magnetization, saturation isothermal remanent magnetization and intrinsic coercivity) were measured for 20 representative rock samples of different lithologies from the Archean Kongling amphibolite to granulite facies terrain of the Yangtze craton. Metasedimentary rocks and tonalitic trondhjemitic granodioritic granitic (TTGG) gneisses show that values of susceptibility κ and saturation isothermal remanent magnetization SIRM are higher than those of amphibolites and gabbros. The felsic gneisses have averages of κ =(1 163±375)×10 -6 SI, SIRM =(18.23±8.38) A/m and R 1=0.083 3± 0.005 7 and the metasedimentary rocks κ =(1 236±823)×10 -6 SI, SIRM =(20.70±10.91) A/m and R I=0.071 4±0.025 2. In contrast, mafic rocks have average κ =(764±316)×10 -6 SI, SIRM = (10.46±3.94)A/m and R 1=0.036±0.009 4, and are dominated by a mixed paramagnetic and ferrimagnetic behavior. Thermal magnetic analyses indicate that magnetite and maghemite of low coercivity are the major carriers of remanent magnetism in the metaclastic sedimentary rocks and TTGG gneisses. The amphibolite and gabbro contain minor amounts of magnetite and pyrrhotite. Magnetism of metaclastic sedimentary rocks and TTGG gneisses is highly heterogeneous; variation coefficients of κ and SIRM are as high as 67 % and 53 % for the former and 32 % and 46 % for the latter. Mineral compositions suggest that biotite may be responsible for the higher magnetism of the metasedimentary rocks. The highest variations in κ, SIRM and R I exhibited by metasedimentary rocks can also be interpreted by their largest absolute variations in biotite mass fraction relative to mafic rocks and felsic gneisses. The average ratio ( Q ) of natural remanent magnetization to induced magnetization of felsic gneisses and metasediments is 0.47 . Ratios ( REM ) of natural remanent to saturation isothermal remanent magnetization ranges between 0.000 001 and 0.027 000 and averages 0.002 540. These values are comparable to those of rocks of similar lithologies from the Archean Taihua high grade terrain of the North China craton and from the Ivrea zone, northern Italy. The dominant phase of magnetism carried by the Kongling rocks is suggested to be thermal remanent magnetization. Consequently, high temperature metamorphism exceeding the Curie point of magnetite (585 ℃) might be responsible for the formation of rock magnetism of the exposed crust in the area of investigation.
文摘Magnetic neutron scattering in Y-type hexagonal ferrite crystals, studied by the author in 1968-1971 and presented in the article showed that the entire density of the so-called magnetic moments of Fe<span style="white-space:nowrap;"><sup>3+</sup></span> ions can significantly shift from the position of their nuclei. As result of these shift the structure in form of the chain magnetic spiral is realized in ferrite lattice. The noted shifts of the “magnetic moments” served as the basis for the author’s assumption that these “moments” are “fig sheets” behind which the magnetic poles (magnetic charges) real existing in the shells of atoms are hidden. In this case, the scattering of neutrons is carried out by magnetic charges, and not theoretical surrogates in the form of magnetic moments. In addition to participating in atomic structures, magnetic charges populate potential conduction zones in conductors, where they are exist in compositions of magnetic dipoles. Under the influence of an external magnetic field, a polarization of magnetic dipoles is realized in the conductor, the field strengths of which are directed against the external magnetic field. It is these dipole magnetic fields that are responsible for such a well-known physical phenomenon as diamagnetism. Under the conditions of noted polarization of magnetic dipoles the author managed to perform mechanical separation of magnetic charges in pairs ±g and to charge experienced bodies (metal plates) by the magnetic charges of one sign. The fact of such a charging was detected through magnetostatic interaction between magnetic charges on the plates using highly sensitive torsion balances. This experiment is presented in detail in this article. The results of these experiments, as well as subsequent experimental and theoretical studies of the author, which, in general composition, were carried out from 1968 to the present, showed that magnetic charges are real structural components of the atoms and substance. So, for example, the atomic shells are not electronic but electromagnetic. The main reason that real magnetic charges were <span style="font-family:Verdana;">“</span><span style="font-family:Verdana;">buried alive” in the existing physical theories is the physics of their confinement in substance forces of which, in its rigidity, is many times greater than the electron confinement forces.</span>
文摘Magnetic structure of Pr6Fe13Ge at room temperature has been investigated by magnetic measurement, Mossbauer effect and neutron diffraction. Magnetic atoms are closely packed up and down the mirror planes at z = 0 and 1/2 and separated by the non-magnetic atoms located on the planes at z= 1/4 and 3/4, which constructs an M/NM/M sandwich structure (M: magnetic, NM: non-magnetic). The intralayer magnetic moments couple ferromagnetically and are out of ab plane at a small angle so as to form a component along c-axis. The interlayer coupling is antiferromagnetic for the ab component while ferromagnetic for the c component.
文摘We examine the electronic and magnetic structures of iron telluride KFe2Te2 using first-principle calculations. We demonstrate that the ground state of this compound is in bicollinear antiferromag- netic order with Fe local moments （- 2.6 μB） that are ferromagnetically aligned along a diagonal direction and antiferromagnetically aligned along the other diagonal in the Fe-Fe square lattice, sim- ilar to the alignment discovered in the parent compound of superconductor α-FeTe. This bicollinear antiferromagnetic order results from the interplay among the nearest, next-nearest, and next-next- nearest neighbor exchange interactions, which are mediated by Te 5p orbitals. This finding may aid our understanding of the interplay between magnetism and superconductivity in the family of iron-based materials.
基金supported by the Ministry of Science and Technology of China(Grants No.2018YFA0305700 and No.2022YFA1403800)the National Natural Science Foundation of China(Grants No.11925408,No.11921004,and No.12188101)+3 种基金the Chinese Academy of Sciences(Grant No.XDB33000000)the Informatization Plan of the Chinese Academy of Sciences(Grant No.CAS WX2021SF-0102)the Condensed Matter Physics Data Center,CASfunding provided by Shanghai Jiao Tong University.
文摘The bulk photovoltaic effect(BPVE)is a second-order optical process in noncentrosymmetric materials that converts the light into DC currents.BPVE is classified into shift current and injection current according to the generation mechanisms and their dependence on the polarization of light is sensitive to the spatial and time-reversal symmetry of materials.In this work,we present a comprehensive study on the BPVE response of EuSn_(2)As_(2) with different magnetic structures through symmetry analysis and first-principles calculation.We demonstrate that the interlayer antiferromagnetic(AFM)EuSn_(2)As_(2) of even-layer breaks the inversion symmetry and has the second-order optical responses.Moreover,the bilayer AFM EuSn_(2)As_(2) not only displays distinct BPVE responses when magnetic moments align in different directions,but also shows symmetry-related responses in two phases which have mutually perpendicular in-plane magnetic moments.Due to the dependence of BPVE responses on the polarization of light and magnetic symmetry,these magnetic structures can be distinguished by the circular polarized light with well-designed experiments.Our work demonstrates the feasibility of the BPVE response as a tool to probe the magnetic structure.
基金This work was financially supported by National Key Research and Development Program of China(No.2016YFB0300500)the National Natural Science Foundation of China(No.51771215)+1 种基金the Ningbo Major Special Projects of the Plan“Science and Technology Innovation 2025”(No.2018B10084)K.C.Wong Magna Fund in Ningbo University。
文摘Electromagnetic interference(EMI)shielding materials with ultrathin,flexible,superior mechanical and thermal management properties are highly desirable for smart and wearable electronics.Here,ultrathin and flexible Ni/Cu/metallic glass/Cu/Ni(Ni/Cu/MG)multilayer composite with alternate magnetic and electrical structures was designed via facial electroless plating of Cu and Ni on an Fe-based metallic glass.The resultant 0.02 mm-thick Ni/Cu/MG composite displays a superior EMI shielding effectiveness(EMI SE)of 35 dB and a great EMI SE/t of 1750 dB/mm,which is greater than those of composites with monotonous multilayer or homogeneous structures.The improved EMI SE originates from the massive ohmic losses,the enhanced internal reflection/absorption,and the abundant interfacial polarization loss.Particularly,Ni/Cu/MG exhibits a high tensile strength of up to 1.2 GPa and outstanding mechanical stability,enabling the EMI SE remains unchanged after 10,000 times of bending.Moreover,Ni/Cu/MG has excellent Joule heating characteristics and thermal stability,which is very suitable for heating components of wearable hyperthermia devices.
