The results of magnetization, magnetoresistivity and magnetocalofic effect （MCE） studies performed on polycrystalline samples of the GdxLa1-xMnSi （x=0.5, 0.6, 0.7, 0.8, 0.9, 1.0） compounds were presented. Complex ...The results of magnetization, magnetoresistivity and magnetocalofic effect （MCE） studies performed on polycrystalline samples of the GdxLa1-xMnSi （x=0.5, 0.6, 0.7, 0.8, 0.9, 1.0） compounds were presented. Complex measurements were carried out on the GdxLa1-xMnSi compounds to determine the influence of substitution in the rare earth （R） sublattice on the magnetic and related properties of these compounds. The compounds with x≤0.6 demonstrated two magnetic phase transitions （ferromagnetic to paramagnetic and antiferro- magnetic to ferromagnetic） both of which were first order. Anomalies in the magnetocaloric effect, electroresistivity and magnetoresistivity were observed in the temperature ranges of the magnetic phase transitions. The temperature dependences of MCE and magnetoresistivity for these compounds correlated with the temperature dependence of magnetization.展开更多
We investigate the anisotropic magnetic transports in topological semimetal TaSb2. The compound shows the large magnetoresistance（MR） without saturation and the metal-insulator-like transition no matter whether the ...We investigate the anisotropic magnetic transports in topological semimetal TaSb2. The compound shows the large magnetoresistance（MR） without saturation and the metal-insulator-like transition no matter whether the magnetic field is parallel to c-axis or a-axis, except that the MR for B‖c is almost twice as large as that of B‖a at low temperatures. The adopted Kohler＇s rule can be obeyed by the MR at distinct temperatures for B‖c,but it is slightly violated as B‖a. The angle-dependent MR measurements exhibit the two-fold rotational symmetry below70 K,consistent with the monoclinic crystal structure of TaSb2. The dumbbell-like picture of angle-dependent MR in TaSb2 suggests a strongly anisotropic Fermi surface at low temperatures. However, it finally loses the two-fold symmetry over 70 K, implying a possible topological phase transition at around the temperature where Tm is related to a metal-insulator-like transition under magnetic fields.展开更多
We present magnetotransport studies on a series of BaFe2_xNixAs2 （0.03 〈 x 〈 0.10） single crystals. In the un- derdoped （x = 0.03） non-superconducting sample, the temperature-dependent resistivity exhibits a pea...We present magnetotransport studies on a series of BaFe2_xNixAs2 （0.03 〈 x 〈 0.10） single crystals. In the un- derdoped （x = 0.03） non-superconducting sample, the temperature-dependent resistivity exhibits a peak at 22 K, which is associated with the onset of filamentary superconductivity （FLSC）. FLSC is suppressed by an external magnetic field in a manner similar to the suppression of bulk superconductivity in an optimally-doped （x = 0.10） compound, suggesting the same possible origin as the bulk superconductivity. Our magnetoresistivity measurements reveal that FLSC persists up to the optimal doping and disappears in the overdoped regime where the long-range antiferromagnetic order is completely suppressed, pointing to a close relation between FLSC and the magnetic order.展开更多
Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which...Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which has a Curie temperature of~290 K and an in-plane easy magnetization axis.Magnetotransport measurements show a positive magnetoresistance(MR)below 50 K,which becomes negative at higher temperatures.An intrinsic anomalous Hall conductivity of 114 S·cm^(-1)is observed in MgMn_(6)Sn_(6) single crystals,consistent with ab initio calculations.Moreover,theoretical predictions indicate that shifting the Fermi level(EF)upward by~70 meV could enhance the AHE to~528 S·cm^(-1).These results position MgMn_(6)Sn_(6) as a promising and tunable platform for exploring topological magnetism and related electronic phenomena.展开更多
Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low...Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K.Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivityρ_(ab)(T)progressively approaches the Fermi-liquid T~2behavior with increasing K doping and reaches a saturation plateau at x≈0.8.The temperature dependence of both H_(c2)^(ab)and H^(c)_(c2)follows the Werthamer-Helfand-Hohenberg model,incorporating orbital and spin paramagnetic effects.For x≤0.8,the orbital effect dominates for H ab,while the Pauli paramagnetic effect prevails for H c.For x>0.8,the Pauli paramagnetic effect becomes dominant in both crystallographic directions.The anisotropy of H_(c2)(0)exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at x=0.8 and a maximum at x=0.9.These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba_(1-x)K_(x)Fe_(2)As_(2)system where the underlying symmetries are broken due to the Fermi surface reconstruction before x=0.9.展开更多
Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular...Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.展开更多
Altermagnets,a class of unconventional antiferromagnets with non-relativistic spin-splitting,offer promising potential for antiferromagnetic spintronic devices.While many altermagnets are limited by either low magneti...Altermagnets,a class of unconventional antiferromagnets with non-relativistic spin-splitting,offer promising potential for antiferromagnetic spintronic devices.While many altermagnets are limited by either low magnetic transition temperatures or weak spin splitting,the recently discovered metal CrSb,with high N′eel temperature(T_(N)=710 K)and significant spin-splitting due to its unique spin space group,provides a robust platform for remarkable tunneling magnetoresistance(TMR)in collinear all-antiferromagnetic tunnel junctions(AATJs).This study systematically investigates the spin-polarized Fermi surface of CrSb and spin-dependent electron transport in CrSb-based AATJs.The CrSb/β-InSe/CrSb junction with a three-monolayer InSe barrier exhibits a TMR ratio of approximately 290%,with energy-dependent analysis revealing TMR ratios that may exceed 850%when considering the shift of the Fermi energy.We also demonstrate the angle-dependent TMR of CrSb-based AATJs by adjusting N′eel vector orientations.Our findings might provide strong theoretical support for CrSb as a versatile building block for all-antiferromagnetic memory devices.展开更多
Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is inv...Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is investigated to gain more insights into the SOC effect in the modification of electronic structure and corresponding magnetic and electrical properties.The high pressure metastable orthorhombic SrIrO_(3)is successfully stabilized by physical and chemical pressures,in which the chemical pressure is induced by Ru doping in Ir site and Mg substitution of Sr position.Detailed structural,magnetic,electrical characterizations and density functional theory(DFT)calculations reveal that the substitution of Ru for Ir renders an enhanced metallic characteristic,while the introduction of Mg into Sr site results in an insulating state with 10.1%negative magnetoresistance at 10 K under 7 T.Theoretical calculations indicate that Ru doping can weaken the SOC effect,leading to the decrease of orbital energy difference between J_(1/2)and J_(3/2),which is favorable for electron transport.On the contrary,Mg doping can enhance the SOC effect,inducing a metal-insulator-transition(MIT).The electronic phase transition is further revealed by DFT calculations,confirming that the strong SOC and electron-electron interactions can lead to the emergence of insulating state.These findings underline the intricate correlations between lattice degrees of freedom and SOC in determining the ground state,which effectively stimulate the physical pressure between like structures by chemical compression.展开更多
Two-dimensional tellurium(2D-Te)exhibits strong spin-orbit coupling and a chiral structure.Studying its magnetotransport properties is crucial for the development of spintronic technologies and the exploration of nove...Two-dimensional tellurium(2D-Te)exhibits strong spin-orbit coupling and a chiral structure.Studying its magnetotransport properties is crucial for the development of spintronic technologies and the exploration of novel device applications.The magnetotransport properties of 2D-Te under varying temperatures and high pressures warrant further study.In this paper,the magnetotransport behavior of 2D-Te under low-temperature and high-pressure conditions is investigated.At room temperature,the magnetoresistance(MR)increases with increasing magnetic field,exhibiting positive MR behavior below 4.3 GPa.During decompression,MR is almost constant with decreasing pressure.MR is more sensitive to pressure at lower temperatures.展开更多
We present a comprehensive investigation into the physical properties of intermetallic ErPd_(2)Si_(2),a compound renowned for its intriguing magnetic and electronic characteristics.We confirm the tetragonal crystal st...We present a comprehensive investigation into the physical properties of intermetallic ErPd_(2)Si_(2),a compound renowned for its intriguing magnetic and electronic characteristics.We confirm the tetragonal crystal structure of ErPd_(2)Si_(2)within the I4/mmm space group.Notably,we observed anisotropic thermal expansion,with the lattice constant a expanding and c contracting between 15 and300 K.This behaviour is attributed to lattice vibrations and electronic contributions.Heat capacity measurements revealed three distinct temperature regimes:T_(1)~3.0 K,T_(N)~4.20 K,and T_(2)~15.31 K.These correspond to thedisappearance of spin-density waves,the onset of an incommensurate antiferromagnetic(AFM)structure,and the crystal-field splitting and/or the presence of short-range spin fluctuations,respectively.Remarkably,the AFM phase transition anomaly was observed exclusively in lowfield magnetization data(120 Oe)at T_(N).A high magnetic field(B=3 T)effectively suppressed this anomaly,likely due to spin-flop and spin-flip transitions.Furthermore,the extracted effective paramagnetic(PM)moments closely matched the expected theoretical value,suggesting a dominant magnetic contribution from localized 4f spins of Er.Additionally,significant differences in resistance(R)values at low temperatures under applied B indicated a magnetoresistance(MR)effect with a minimum value of-4.36%.Notably,the measured MR effect exhibited anisotropic behavior,where changes in the strength or direction of the applied B induced variations in the MR effect.A twofold symmetry of R was discerned at 3 and9 T,originating from the orientation of spin moments relative to the applied B.Intriguingly,above T_(N),shortrange spin fluctuations also displayed a preferred orientation along the c-axis due to single-ion anisotropy.Moreover,the R demonstrated a clear B dependence below30 K.The magnetic-field point where R transitions from linear B dependence to a stable state increased with temperature:~3 T(at 2 K),~4.5 T(at 4 K),and~6 T(at 10 K).Our study sheds light on the magnetic and electronic properties of ErPd_(2)Si_(2),offering valuable insights for potential applications in spintronics and quantum technologies.展开更多
We investigate the surface acoustic wave(SAW)modulation of the exchange bias field(H_(EB))in Py/IrMn films deposited on LiNbO_(3)substrates.We measured the anisotropic magnetoresistance(AMR)of the multilayer film when...We investigate the surface acoustic wave(SAW)modulation of the exchange bias field(H_(EB))in Py/IrMn films deposited on LiNbO_(3)substrates.We measured the anisotropic magnetoresistance(AMR)of the multilayer film when continuous SAW or pulsed SAW were applied and obtained H_(EB).With continuous SAW,the H_(EB)decreases continuously with power.While in the case of pulsed SAW,the H_(EB)first decreases and then stabilizes.Compared to pulsed SAW,the thermal effects from the continuous SAW lead to the continuous decrease of H_(EB)at higher SAW power,which is verified by the measurement of H_(EB)at different temperatures and input currents.Furthermore,our results show that pulsed SAW can effectively avoid thermal effects.The decrease of H_(EB)at smaller power in both continuous and pulsed SAW is mainly due to the SAW-induced dynamic strain field,which leads to a small perturbation in the magnetic moment of the FM layer.Combined with the AMR values measured at different angles during the saturation field,we believe that the SAW-induced dynamic strain field causes a 15°angle between the magnetic moment and the easy axis.Our experiments provide a different approach to manipulating H_(EB),opening up a potential avenue for future manipulation of antiferromagnetic moments.展开更多
We report the manipulation of ferromagnetism in magnetic semiconductor Ba(Zn,Mn,Cu)_(2)As_(2)through chemical pressure.The substitutions of Sr for Ba and Sb for As introduce positive and negative chemical pressures,re...We report the manipulation of ferromagnetism in magnetic semiconductor Ba(Zn,Mn,Cu)_(2)As_(2)through chemical pressure.The substitutions of Sr for Ba and Sb for As introduce positive and negative chemical pressures,respectively;neither Sr doping nor Sb doping change the tetragonal crystal structure.Based on Ba(Zn_(0.75)Mn_(0.125)Cu_(0.125))_(2)As_(2)with T_(C)~34 K,10%Sr/Ba substitutions significantly improve T_(C)by~15%to 39 K,whereas 10%Sb/As substitutions substantially reduce TCby~47%to 18 K.The AC magnetic susceptibility measurements indicate that Sr-doped and Sb-doped samples evolve into a spin glass state below the spin freezing temperature Tf.Electrical transport measurements demonstrate that Sr-doped specimens retain semiconducting behavior;additionally,they display a significant negative magnetoresistance effect under applied magnetic fields and the magnetoresistance reaches~-19%at 8 T.展开更多
The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific ...The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific configuration of applied magnetics fields and current and can persist up to 20 K,much higher than the Ne'el temperature(T_(N)≈1.9 K).Experiments and first-principles calculations suggest that the observed large negative MR is derived from a magnetic field that reconstructs the band structure and induces a Weyl point,which changes the carrier concentration.展开更多
In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately dete...In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately detect any form of relative movement of objects without physical contact.For instance,in the precise control of robotic arms or machine tools,a permanent magnet is used as a reference.The magnetic sensor detects the relative movement of magnet by sensing changes in the magnetic field strength.These changes are converted into electrical signals,which are fed back to the control system,enabling accurate positioning and control of the device.This advanced detection technology not only greatly enhances measurement precision but also significantly extends the lifespan of equipment.Among various types of magnetic field sensors,magnetoresistive(MR)sensors stand out for their exceptional performance[1].The high sensitivity allows them to detect minimal changes of magnetic fields in high-precision measurements.Today,MR sensors are widely used across numerous fields,including automobile industries,information processing and storage,navigation systems,biomedical applications,etc[1,2].With their outstanding performance and wide-ranging applications,MR sensors are at the forefront of sensor technology.展开更多
Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential top...Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential topological materials,have garnered significant attention.In this study,we synthesized single crystals of ZrBi_(2) and performed electrical and specific heat measurements on them.The resistivity of ZrBi_(2) displays metallic behavior with a high residual resistance ratio.Notably,the MR of ZrBi_(2) reaches approximately 2.0×10^(3)%at 2 K and 16 T without saturation.Weak Shubnikov-de Haas oscillations with two frequencies were observed above 13.5 T,which correspond to 237 T and 663 T.Hall effect fitting yields nearly equal concentrations of electron and hole carriers with concentrations of approximately 10^(21)cm^(-3)and mobilities of approximately 5000 cm^(2)·V^(-1)·s^(-1)at 2 K.The XMR could be attributed to the electron-hole compensation with high mobility.展开更多
Two-dimensional van der Waals(vdW)magnetic materials,characterized by their tunable magnetism,spin transport properties,and remarkable quantum effects,provide significant promise for the development of efficient,low-p...Two-dimensional van der Waals(vdW)magnetic materials,characterized by their tunable magnetism,spin transport properties,and remarkable quantum effects,provide significant promise for the development of efficient,low-power spintronic devices.Intriguingly,the rare earth tritelluride(RTe3)materials have attracted great attention due to their unique magnetic structure,exotic electronic properties,multiple charge density wave(CDW),and superconductivity under pressure.Here,we report the successful synthesis of high-quality DyTe_(3)single crystals using a self-flux method.DyTe_(3)shows an antiferromagnetic transition at 4.5 K and demonstrates the magnetic field-induced ferromagnetism.The high-quality DyTe_(3)single crystal demonstrates outstanding transport properties,featuring a high carrier mobility of approximately1.4×10^(4)cm^(2)·V^(-1)·s^(-1)and large linear magnetoresistance of 1300%.Furthermore,distinct Shubnikov-de Haas(SdH)oscillations are observed in DyTe_(3),revealing a small Fermi pocket and an effective mass of 0.24 me.Remarkably,the unconventional in-plane negative magnetoresistances appear along the a-axis below 2 T and c-axis until 9 T from 2 K to17 K,which are attributed to the complex helimagnetic structures caused by CDW coupling and weak single-ion anisotropy.Our findings offer a significant platform for understanding the complex magnetoresistance behavior and quantum transport effects in RTe3-type materials,holding great promise for advancing applications in electronic and spintronic devices.展开更多
EuB_(6),a magnetic topological semimetal,has attracted considerable attention in recent years due to its rich intriguing physical properties,including a colossal negative magnetoresistance(CNMR)ratio exceeding-80%,a t...EuB_(6),a magnetic topological semimetal,has attracted considerable attention in recent years due to its rich intriguing physical properties,including a colossal negative magnetoresistance(CNMR)ratio exceeding-80%,a topological phase transition and a predicted quantum anomalous Hall effect(QAHE)approaching the two-dimensional(2D)limit.Yet,studies of the influence of the dimensionality approaching 2D on the electronic transport properties of EuB_(6) are still scarce.In this work,EuB_(6) thin sheets with thicknesses ranging from 35μm to 180μm were successfully fabricated through careful mechanical polishing of high-quality EuB_(6) single crystals.The reduced thickness,temperature and magnetic field have a strong influence on the electronic transport properties,including the CNMR and carrier concentration of EuB_(6) thin sheets.As the thickness of EuB_(6) thin sheets decreases from 180μm to 35μm,the magnetization transition temperature and the corresponding suppressing temperature of the Kondo effect decrease from 15.2 K to 10.9 K,while the CNMR ratio increases from-87.2%to-90.8%.Furthermore,the weak antilocalization effect transits to a weak localization effect and the carrier concentration increases by 9.4%at 30 K in a 35μm EuB_(6) thin sheet compared to the value reported for a 180μm thin sheet.Our findings demonstrate an obvious tunable effect of the reduced dimensionality on the transport properties of EuB_(6) along with the temperature and magnetic field,which could provide a route to exploring the QAHE near the 2D limit in EuB_(6) and other topological semimetals.展开更多
We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-...We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-Ga ratio in the AlGaSb barrier layer,the quantum confinement of the heterostructure is significantly enhanced.Alongside a giant magnetoresistance ratio of 3.65×10^(5)%,the two-carrier transport model from Hall measurements reveals an ultra-high electron mobility of 7.18×10^(5)cm^(2)·V^(-1)·s^(-1)at low temperatures.Meanwhile,pronounced Shubnikov-de Haas(SdH)quantum oscillations persist up to 30 K,and their single-frequency feature indicates a well-defined Fermi surface without subband mixing in the two-dimensional electron gas channel.Moreover,the large effective g-factor and tilted-field-induced orbital effect lead to the observation of split SdH peaks at large magnetic fields.Our results validate that AlGaSb/InAs quantum well heterostructures are suitable candidates for constructing energy-efficient topological spintronic devices.展开更多
Mn_(3)Si_(2)Te_(6) is a ferrimagnetic nodal-line semiconductor with colossal angular magnetoresistance at ambient pressure.In this work,we investigated the effect of hydrostatic pressure on its electrical transport pr...Mn_(3)Si_(2)Te_(6) is a ferrimagnetic nodal-line semiconductor with colossal angular magnetoresistance at ambient pressure.In this work,we investigated the effect of hydrostatic pressure on its electrical transport properties,magnetic transition,and crystal structure by measuring resistivity,DC and AC magnetic susceptibility,and XRD under various pressures up to~20 GPa.Our results confirmed the occurrence of pressure-induced structural transition at P_(c)≈10–12 GPa accompanied by a concurrent drop of room-temperature resistance in Mn_(3)Si_(2)Te_(6).In the low-pressure phase at PP_(c),the sample exhibits a metallic behavior in the whole temperature range and its resistivity exhibits a kink anomaly at T_(M),characteristic of critical scattering around a magnetic transition.Recovery of the Raman spectrum upon decompression indicated that pressure-induced structural transition is reversible without amorphization under hydrostatic pressure conditions.Our present work not only resolves some existing controversial issues but also provides new insights into pressure-driven diverse behaviors of Mn_(3)Si_(2)Te_(6).展开更多
We report a systematic study on the transport properties of(Bi_(0.2)Sb_(0.8))_(2)Te_(3)and(Bi_(0.4)Sb_(0.6))_(2)Te_(3)nanoplates with a thickness of about 6 nm grown by chemical vapor deposition(CVD)on Si/SiO_(2)subst...We report a systematic study on the transport properties of(Bi_(0.2)Sb_(0.8))_(2)Te_(3)and(Bi_(0.4)Sb_(0.6))_(2)Te_(3)nanoplates with a thickness of about 6 nm grown by chemical vapor deposition(CVD)on Si/SiO_(2)substrate.We achieve a significant ambipolar field effect in the two samples with different compositions by applying back-gate voltage,successfully tuning the Fermi level across the Dirac point of surface states.It is found that the Hall resistance exhibits strong non-linear behavior and magnetic field induced sign change of the slope when the Fermi level is near the Dirac point,indicating the coexistence of n-type and p-type carriers.Moreover,this coincides with the striking crossover from weak antilocalization(WAL)to linear magnetoresistance(LMR).These gate and temperature dependent magneto-transport studies provide a deeper insight into the nature of LMR and WAL in topological materials.展开更多
基金supported by the Federal Program on Support of Leading Scientific Schools (НШ-8701.2006.2)
文摘The results of magnetization, magnetoresistivity and magnetocalofic effect （MCE） studies performed on polycrystalline samples of the GdxLa1-xMnSi （x=0.5, 0.6, 0.7, 0.8, 0.9, 1.0） compounds were presented. Complex measurements were carried out on the GdxLa1-xMnSi compounds to determine the influence of substitution in the rare earth （R） sublattice on the magnetic and related properties of these compounds. The compounds with x≤0.6 demonstrated two magnetic phase transitions （ferromagnetic to paramagnetic and antiferro- magnetic to ferromagnetic） both of which were first order. Anomalies in the magnetocaloric effect, electroresistivity and magnetoresistivity were observed in the temperature ranges of the magnetic phase transitions. The temperature dependences of MCE and magnetoresistivity for these compounds correlated with the temperature dependence of magnetization.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61401136,11604299 and 61376094the Zhejiang Natural Science Foundation of China under Grant No LY18F010019+1 种基金the Open Program from Wuhan National High Magnetic Field Center under Grant No 2016KF03the General Program of Natural Science Foundation of Jiangsu Province under Grant No BK20171440
文摘We investigate the anisotropic magnetic transports in topological semimetal TaSb2. The compound shows the large magnetoresistance（MR） without saturation and the metal-insulator-like transition no matter whether the magnetic field is parallel to c-axis or a-axis, except that the MR for B‖c is almost twice as large as that of B‖a at low temperatures. The adopted Kohler＇s rule can be obeyed by the MR at distinct temperatures for B‖c,but it is slightly violated as B‖a. The angle-dependent MR measurements exhibit the two-fold rotational symmetry below70 K,consistent with the monoclinic crystal structure of TaSb2. The dumbbell-like picture of angle-dependent MR in TaSb2 suggests a strongly anisotropic Fermi surface at low temperatures. However, it finally loses the two-fold symmetry over 70 K, implying a possible topological phase transition at around the temperature where Tm is related to a metal-insulator-like transition under magnetic fields.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB821400,2012CB921302,and 2015CB921303)the National Natural Science Foundation of China(Grant Nos.11274237,91121004,51228201,11004238,and 11374011)
文摘We present magnetotransport studies on a series of BaFe2_xNixAs2 （0.03 〈 x 〈 0.10） single crystals. In the un- derdoped （x = 0.03） non-superconducting sample, the temperature-dependent resistivity exhibits a peak at 22 K, which is associated with the onset of filamentary superconductivity （FLSC）. FLSC is suppressed by an external magnetic field in a manner similar to the suppression of bulk superconductivity in an optimally-doped （x = 0.10） compound, suggesting the same possible origin as the bulk superconductivity. Our magnetoresistivity measurements reveal that FLSC persists up to the optimal doping and disappears in the overdoped regime where the long-range antiferromagnetic order is completely suppressed, pointing to a close relation between FLSC and the magnetic order.
基金Project supported by the National Natural Science Foundation of China(Grant No.12204347)National Key Research and Development Program of China(Grant No.2022YFA1402600)the Fund from Beijing National Laboratory for Condensed Matter Physics(Grant No.2023BNLCMPKF011)。
文摘Kagome magnets are of growing interest due to their topological electronic structures and unconventional magnetic behavior.Here,we report on the anomalous Hall effect(AHE)in the kagome ferromagnet MgMn_(6)Sn_(6),which has a Curie temperature of~290 K and an in-plane easy magnetization axis.Magnetotransport measurements show a positive magnetoresistance(MR)below 50 K,which becomes negative at higher temperatures.An intrinsic anomalous Hall conductivity of 114 S·cm^(-1)is observed in MgMn_(6)Sn_(6) single crystals,consistent with ab initio calculations.Moreover,theoretical predictions indicate that shifting the Fermi level(EF)upward by~70 meV could enhance the AHE to~528 S·cm^(-1).These results position MgMn_(6)Sn_(6) as a promising and tunable platform for exploring topological magnetism and related electronic phenomena.
基金supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1611100,2023YFA1406100,and 2018YFA0704201)the Systematic Fundamental Research Program Leveraging Major Scientific and Technological Infrastructure,Chinese Academy of Sciences(Grant No.JZHKYPT-2021-08)+1 种基金the National Natural Science Foundation of China(Grant Nos.11704385,11874359,and 12274444)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB25000000)。
文摘Temperature-dependent resistivity,upper critical field H_(c2)and its anisotropy in overdoped superconducting Ba_(1-x)K_x Fe_2As_2(x=0.6-1)single crystals have been measured in steady magnetic fields up to 44 T and low temperatures down to 0.4 K.Analysis using both the quadratic term and power-law fitting demonstrates that the in-plane resistivityρ_(ab)(T)progressively approaches the Fermi-liquid T~2behavior with increasing K doping and reaches a saturation plateau at x≈0.8.The temperature dependence of both H_(c2)^(ab)and H^(c)_(c2)follows the Werthamer-Helfand-Hohenberg model,incorporating orbital and spin paramagnetic effects.For x≤0.8,the orbital effect dominates for H ab,while the Pauli paramagnetic effect prevails for H c.For x>0.8,the Pauli paramagnetic effect becomes dominant in both crystallographic directions.The anisotropy of H_(c2)(0)exhibits a discontinuity in its dependence on K doping concentration with a significant enhancement at x=0.8 and a maximum at x=0.9.These experimental results indicate that the electron correlation effect is enhanced in the heavily overdoped Ba_(1-x)K_(x)Fe_(2)As_(2)system where the underlying symmetries are broken due to the Fermi surface reconstruction before x=0.9.
基金supported by the National Key R&D Program of China(Grant No.2022YFB3505301)the National Key R&D Program of Shanxi Province(Grant No.202302050201014)+1 种基金the National Natural Science Foundation of China(Grant No.12304148)the Natural Science Basic Research Program of Shanxi Province(Grant No.202203021222219)。
文摘Multiferroic tunnel junctions(MFTJs),which combine tunneling magnetoresistance(TMR)and electroresistance(TER)efects,have emerged as key candidates for data storage.Two-dimensional van der Waals(vdW)MFTJs,in particular,are promising spintronic devices for the post-Moore era.However,these vdW MFTJs are typically based on multiferroics composed of ferromagnetic and ferroelectric materials or multilayer magnetic materials with sliding ferroelectricity,which increases device fabrication complexity.In this work,we design a vdW MFTJ using bilayer MoPtGe_(2)S_(6),a material with homologous multiferroicity in each monolayer,combined with symmetric PtTe_(2)electrodes.Using frst-principles calculations based on density functional theory and nonequilibrium Green's functions,we theoretically explore the spin-polarized electronic transport properties of this MFTJ.By controlling the ferroelectric and ferromagnetic polarization directions of bilayer MoPtGe_(2)S_(6),the MFTJ can exhibit six distinct non-volatile resistance states,with maximum TMR(137%)and TER(1943%)ratios.Under biaxial strain,TMR and TER can increase to 265%and 4210%,respectively.The TER ratio also increases to 2186%under a 0.1 V bias voltage.Remarkably,the MFTJ exhibits a pronounced spin-fltering and a signifcant negative diferential resistance efect.These fndings not only highlight the potential of monolayer multiferroic MoPtGe_(2)S_(6)for MFTJs but also ofer valuable theoretical insights for future experimental investigations.
基金supported by the National Natural Science Foundation of China(Grant Nos.T2394475,T2394470,T2394471,and 12174129)the China Postdoctoral Science Foundation(Grant No.2023M741269).
文摘Altermagnets,a class of unconventional antiferromagnets with non-relativistic spin-splitting,offer promising potential for antiferromagnetic spintronic devices.While many altermagnets are limited by either low magnetic transition temperatures or weak spin splitting,the recently discovered metal CrSb,with high N′eel temperature(T_(N)=710 K)and significant spin-splitting due to its unique spin space group,provides a robust platform for remarkable tunneling magnetoresistance(TMR)in collinear all-antiferromagnetic tunnel junctions(AATJs).This study systematically investigates the spin-polarized Fermi surface of CrSb and spin-dependent electron transport in CrSb-based AATJs.The CrSb/β-InSe/CrSb junction with a three-monolayer InSe barrier exhibits a TMR ratio of approximately 290%,with energy-dependent analysis revealing TMR ratios that may exceed 850%when considering the shift of the Fermi energy.We also demonstrate the angle-dependent TMR of CrSb-based AATJs by adjusting N′eel vector orientations.Our findings might provide strong theoretical support for CrSb as a versatile building block for all-antiferromagnetic memory devices.
基金supported by the National Natural Science Foundation of China(NSFC,No.22090041)the Guangdong Basic and Applied Basic Research Foundation(No.2022B1515120014)。
文摘Spin-orbit coupling(SOC)plays a vital role in determining the ground state and forming novel electronic states of matter where heavy elements are involved.Here,the prototypical perovskite iridate oxide SrIrO_(3)is investigated to gain more insights into the SOC effect in the modification of electronic structure and corresponding magnetic and electrical properties.The high pressure metastable orthorhombic SrIrO_(3)is successfully stabilized by physical and chemical pressures,in which the chemical pressure is induced by Ru doping in Ir site and Mg substitution of Sr position.Detailed structural,magnetic,electrical characterizations and density functional theory(DFT)calculations reveal that the substitution of Ru for Ir renders an enhanced metallic characteristic,while the introduction of Mg into Sr site results in an insulating state with 10.1%negative magnetoresistance at 10 K under 7 T.Theoretical calculations indicate that Ru doping can weaken the SOC effect,leading to the decrease of orbital energy difference between J_(1/2)and J_(3/2),which is favorable for electron transport.On the contrary,Mg doping can enhance the SOC effect,inducing a metal-insulator-transition(MIT).The electronic phase transition is further revealed by DFT calculations,confirming that the strong SOC and electron-electron interactions can lead to the emergence of insulating state.These findings underline the intricate correlations between lattice degrees of freedom and SOC in determining the ground state,which effectively stimulate the physical pressure between like structures by chemical compression.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(Grant No.12304067)+1 种基金the Natural Science Foundation of Shandong Province(Grant Nos.ZR2021QA087 and ZR2021QA092)the Special Construction Project Fund for Shandong Province Taishan Scholars。
文摘Two-dimensional tellurium(2D-Te)exhibits strong spin-orbit coupling and a chiral structure.Studying its magnetotransport properties is crucial for the development of spintronic technologies and the exploration of novel device applications.The magnetotransport properties of 2D-Te under varying temperatures and high pressures warrant further study.In this paper,the magnetotransport behavior of 2D-Te under low-temperature and high-pressure conditions is investigated.At room temperature,the magnetoresistance(MR)increases with increasing magnetic field,exhibiting positive MR behavior below 4.3 GPa.During decompression,MR is almost constant with decreasing pressure.MR is more sensitive to pressure at lower temperatures.
基金supported by the Science and Technology Development Fund,Macao SAR,China(File Nos.0090/2021/A2 and 0104/2024/AFJ)University of Macao(MYRG-GRG2024-00158-IAPME)+3 种基金the support from the National Natural Science Foundation of China(No.52275467)the support from the National Natural Science Foundation of China(No.52271037)Shaanxi Provincial Natural Science Fundamental Research Program,China(No.2023-JC-ZD-23)the Fundamental Research Funds for the Central Universities of China(No.D5000240307)
文摘We present a comprehensive investigation into the physical properties of intermetallic ErPd_(2)Si_(2),a compound renowned for its intriguing magnetic and electronic characteristics.We confirm the tetragonal crystal structure of ErPd_(2)Si_(2)within the I4/mmm space group.Notably,we observed anisotropic thermal expansion,with the lattice constant a expanding and c contracting between 15 and300 K.This behaviour is attributed to lattice vibrations and electronic contributions.Heat capacity measurements revealed three distinct temperature regimes:T_(1)~3.0 K,T_(N)~4.20 K,and T_(2)~15.31 K.These correspond to thedisappearance of spin-density waves,the onset of an incommensurate antiferromagnetic(AFM)structure,and the crystal-field splitting and/or the presence of short-range spin fluctuations,respectively.Remarkably,the AFM phase transition anomaly was observed exclusively in lowfield magnetization data(120 Oe)at T_(N).A high magnetic field(B=3 T)effectively suppressed this anomaly,likely due to spin-flop and spin-flip transitions.Furthermore,the extracted effective paramagnetic(PM)moments closely matched the expected theoretical value,suggesting a dominant magnetic contribution from localized 4f spins of Er.Additionally,significant differences in resistance(R)values at low temperatures under applied B indicated a magnetoresistance(MR)effect with a minimum value of-4.36%.Notably,the measured MR effect exhibited anisotropic behavior,where changes in the strength or direction of the applied B induced variations in the MR effect.A twofold symmetry of R was discerned at 3 and9 T,originating from the orientation of spin moments relative to the applied B.Intriguingly,above T_(N),shortrange spin fluctuations also displayed a preferred orientation along the c-axis due to single-ion anisotropy.Moreover,the R demonstrated a clear B dependence below30 K.The magnetic-field point where R transitions from linear B dependence to a stable state increased with temperature:~3 T(at 2 K),~4.5 T(at 4 K),and~6 T(at 10 K).Our study sheds light on the magnetic and electronic properties of ErPd_(2)Si_(2),offering valuable insights for potential applications in spintronics and quantum technologies.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174166 and 12304144)the Fund from Beijing National Laboratory for Condensed Matter Physics(Grant No.2024BNLCMPKF013)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-22).
文摘We investigate the surface acoustic wave(SAW)modulation of the exchange bias field(H_(EB))in Py/IrMn films deposited on LiNbO_(3)substrates.We measured the anisotropic magnetoresistance(AMR)of the multilayer film when continuous SAW or pulsed SAW were applied and obtained H_(EB).With continuous SAW,the H_(EB)decreases continuously with power.While in the case of pulsed SAW,the H_(EB)first decreases and then stabilizes.Compared to pulsed SAW,the thermal effects from the continuous SAW lead to the continuous decrease of H_(EB)at higher SAW power,which is verified by the measurement of H_(EB)at different temperatures and input currents.Furthermore,our results show that pulsed SAW can effectively avoid thermal effects.The decrease of H_(EB)at smaller power in both continuous and pulsed SAW is mainly due to the SAW-induced dynamic strain field,which leads to a small perturbation in the magnetic moment of the FM layer.Combined with the AMR values measured at different angles during the saturation field,we believe that the SAW-induced dynamic strain field causes a 15°angle between the magnetic moment and the easy axis.Our experiments provide a different approach to manipulating H_(EB),opening up a potential avenue for future manipulation of antiferromagnetic moments.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1402701 and 2022YFA1403202)the National Natural Science Foundation of China(Grant No.12074333)the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C01002)。
文摘We report the manipulation of ferromagnetism in magnetic semiconductor Ba(Zn,Mn,Cu)_(2)As_(2)through chemical pressure.The substitutions of Sr for Ba and Sb for As introduce positive and negative chemical pressures,respectively;neither Sr doping nor Sb doping change the tetragonal crystal structure.Based on Ba(Zn_(0.75)Mn_(0.125)Cu_(0.125))_(2)As_(2)with T_(C)~34 K,10%Sr/Ba substitutions significantly improve T_(C)by~15%to 39 K,whereas 10%Sb/As substitutions substantially reduce TCby~47%to 18 K.The AC magnetic susceptibility measurements indicate that Sr-doped and Sb-doped samples evolve into a spin glass state below the spin freezing temperature Tf.Electrical transport measurements demonstrate that Sr-doped specimens retain semiconducting behavior;additionally,they display a significant negative magnetoresistance effect under applied magnetic fields and the magnetoresistance reaches~-19%at 8 T.
基金financially supported by the National Key R&D Program of China(No.2022YFA1402600)the National Natural Science Foundation of China(Nos.12304150 and 52161135108)support by the National Science Centre(Poland)(No.2021/40/Q/ST5/00066)。
文摘The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific configuration of applied magnetics fields and current and can persist up to 20 K,much higher than the Ne'el temperature(T_(N)≈1.9 K).Experiments and first-principles calculations suggest that the observed large negative MR is derived from a magnetic field that reconstructs the band structure and induces a Weyl point,which changes the carrier concentration.
文摘In the modern technological landscape,magnetic field sensors play a crucial role and are indispensable across a range of high-tech applications[1].In conjunction with magnets,magnetic field sensors can accurately detect any form of relative movement of objects without physical contact.For instance,in the precise control of robotic arms or machine tools,a permanent magnet is used as a reference.The magnetic sensor detects the relative movement of magnet by sensing changes in the magnetic field strength.These changes are converted into electrical signals,which are fed back to the control system,enabling accurate positioning and control of the device.This advanced detection technology not only greatly enhances measurement precision but also significantly extends the lifespan of equipment.Among various types of magnetic field sensors,magnetoresistive(MR)sensors stand out for their exceptional performance[1].The high sensitivity allows them to detect minimal changes of magnetic fields in high-precision measurements.Today,MR sensors are widely used across numerous fields,including automobile industries,information processing and storage,navigation systems,biomedical applications,etc[1,2].With their outstanding performance and wide-ranging applications,MR sensors are at the forefront of sensor technology.
基金Project supported by the National Natural Science Foundation of China(Grant No.12274440)the National Key R&D Program of China(Grant No.2022YFA1403903)the Synergetic Extreme Condition User Facility(SECUF)。
文摘Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential topological materials,have garnered significant attention.In this study,we synthesized single crystals of ZrBi_(2) and performed electrical and specific heat measurements on them.The resistivity of ZrBi_(2) displays metallic behavior with a high residual resistance ratio.Notably,the MR of ZrBi_(2) reaches approximately 2.0×10^(3)%at 2 K and 16 T without saturation.Weak Shubnikov-de Haas oscillations with two frequencies were observed above 13.5 T,which correspond to 237 T and 663 T.Hall effect fitting yields nearly equal concentrations of electron and hole carriers with concentrations of approximately 10^(21)cm^(-3)and mobilities of approximately 5000 cm^(2)·V^(-1)·s^(-1)at 2 K.The XMR could be attributed to the electron-hole compensation with high mobility.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62488201 and 1240041502)the Ministry of Science and Technology of China(Grant No.2022YFA1204100)+1 种基金the Chinese Academy of Sciences(Grant No.XDB33030100)the Innovation Program of Quantum Science and Technology(Grant No.2021ZD0302700)。
文摘Two-dimensional van der Waals(vdW)magnetic materials,characterized by their tunable magnetism,spin transport properties,and remarkable quantum effects,provide significant promise for the development of efficient,low-power spintronic devices.Intriguingly,the rare earth tritelluride(RTe3)materials have attracted great attention due to their unique magnetic structure,exotic electronic properties,multiple charge density wave(CDW),and superconductivity under pressure.Here,we report the successful synthesis of high-quality DyTe_(3)single crystals using a self-flux method.DyTe_(3)shows an antiferromagnetic transition at 4.5 K and demonstrates the magnetic field-induced ferromagnetism.The high-quality DyTe_(3)single crystal demonstrates outstanding transport properties,featuring a high carrier mobility of approximately1.4×10^(4)cm^(2)·V^(-1)·s^(-1)and large linear magnetoresistance of 1300%.Furthermore,distinct Shubnikov-de Haas(SdH)oscillations are observed in DyTe_(3),revealing a small Fermi pocket and an effective mass of 0.24 me.Remarkably,the unconventional in-plane negative magnetoresistances appear along the a-axis below 2 T and c-axis until 9 T from 2 K to17 K,which are attributed to the complex helimagnetic structures caused by CDW coupling and weak single-ion anisotropy.Our findings offer a significant platform for understanding the complex magnetoresistance behavior and quantum transport effects in RTe3-type materials,holding great promise for advancing applications in electronic and spintronic devices.
基金Project supported by the National Key R&D Program of China(Grant No.2022YFA1204100)the National Natural Science Foundation of China(Grant No.62488201)+1 种基金the Chinese Academy of Sciences(Grant Nos.XDB33030000 and YSBR-053)Innovation Program of Quantum Science and Technology(Grant No.2021ZD0302700)。
文摘EuB_(6),a magnetic topological semimetal,has attracted considerable attention in recent years due to its rich intriguing physical properties,including a colossal negative magnetoresistance(CNMR)ratio exceeding-80%,a topological phase transition and a predicted quantum anomalous Hall effect(QAHE)approaching the two-dimensional(2D)limit.Yet,studies of the influence of the dimensionality approaching 2D on the electronic transport properties of EuB_(6) are still scarce.In this work,EuB_(6) thin sheets with thicknesses ranging from 35μm to 180μm were successfully fabricated through careful mechanical polishing of high-quality EuB_(6) single crystals.The reduced thickness,temperature and magnetic field have a strong influence on the electronic transport properties,including the CNMR and carrier concentration of EuB_(6) thin sheets.As the thickness of EuB_(6) thin sheets decreases from 180μm to 35μm,the magnetization transition temperature and the corresponding suppressing temperature of the Kondo effect decrease from 15.2 K to 10.9 K,while the CNMR ratio increases from-87.2%to-90.8%.Furthermore,the weak antilocalization effect transits to a weak localization effect and the carrier concentration increases by 9.4%at 30 K in a 35μm EuB_(6) thin sheet compared to the value reported for a 180μm thin sheet.Our findings demonstrate an obvious tunable effect of the reduced dimensionality on the transport properties of EuB_(6) along with the temperature and magnetic field,which could provide a route to exploring the QAHE near the 2D limit in EuB_(6) and other topological semimetals.
基金supported by R&D the National Key Program of China(Grant No.2021YFA0715503)the Major Project ofShanghai Municipal Science and Technology(Grant No.2018SHZDZX02)the ShanghaiTech Mate rial Device and Soft Matter Nano-fabrication Labs(No.SMN180827).
文摘We report the epitaxial growth of high-quality Al_(0.8)Ga_(0.2)Sb/InAs/Al_(0.8)Ga_(0.2)Sb quantum well films characterized by high carrier mobility and strong spin-orbit coupling.By appropriately optimizing the Al-to-Ga ratio in the AlGaSb barrier layer,the quantum confinement of the heterostructure is significantly enhanced.Alongside a giant magnetoresistance ratio of 3.65×10^(5)%,the two-carrier transport model from Hall measurements reveals an ultra-high electron mobility of 7.18×10^(5)cm^(2)·V^(-1)·s^(-1)at low temperatures.Meanwhile,pronounced Shubnikov-de Haas(SdH)quantum oscillations persist up to 30 K,and their single-frequency feature indicates a well-defined Fermi surface without subband mixing in the two-dimensional electron gas channel.Moreover,the large effective g-factor and tilted-field-induced orbital effect lead to the observation of split SdH peaks at large magnetic fields.Our results validate that AlGaSb/InAs quantum well heterostructures are suitable candidates for constructing energy-efficient topological spintronic devices.
基金supported by the National Key R&D Program of China (Grant Nos. 2023YFA1406100, 2022YFA1403900, 2024YFA1408400, 2021YFA1400200, 2022YFA1403800, and 2023YFA1406500)the National Natural Science Foundation of China (Grant Nos. 12174424, 12025408, 11921004, U22A6005, and 12274459)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2023007)the Chinese Academy of Sciences President’s International Fellowship Initiative (Grant No. 2024PG0003)。
文摘Mn_(3)Si_(2)Te_(6) is a ferrimagnetic nodal-line semiconductor with colossal angular magnetoresistance at ambient pressure.In this work,we investigated the effect of hydrostatic pressure on its electrical transport properties,magnetic transition,and crystal structure by measuring resistivity,DC and AC magnetic susceptibility,and XRD under various pressures up to~20 GPa.Our results confirmed the occurrence of pressure-induced structural transition at P_(c)≈10–12 GPa accompanied by a concurrent drop of room-temperature resistance in Mn_(3)Si_(2)Te_(6).In the low-pressure phase at PP_(c),the sample exhibits a metallic behavior in the whole temperature range and its resistivity exhibits a kink anomaly at T_(M),characteristic of critical scattering around a magnetic transition.Recovery of the Raman spectrum upon decompression indicated that pressure-induced structural transition is reversible without amorphization under hydrostatic pressure conditions.Our present work not only resolves some existing controversial issues but also provides new insights into pressure-driven diverse behaviors of Mn_(3)Si_(2)Te_(6).
基金financially supported by the National Natural Science Foundation of China(Nos.52201233,52371204,and 52031014).
文摘We report a systematic study on the transport properties of(Bi_(0.2)Sb_(0.8))_(2)Te_(3)and(Bi_(0.4)Sb_(0.6))_(2)Te_(3)nanoplates with a thickness of about 6 nm grown by chemical vapor deposition(CVD)on Si/SiO_(2)substrate.We achieve a significant ambipolar field effect in the two samples with different compositions by applying back-gate voltage,successfully tuning the Fermi level across the Dirac point of surface states.It is found that the Hall resistance exhibits strong non-linear behavior and magnetic field induced sign change of the slope when the Fermi level is near the Dirac point,indicating the coexistence of n-type and p-type carriers.Moreover,this coincides with the striking crossover from weak antilocalization(WAL)to linear magnetoresistance(LMR).These gate and temperature dependent magneto-transport studies provide a deeper insight into the nature of LMR and WAL in topological materials.
