Electric field control of magnetism through nanoionics has attracted tremendous attention owing to its high efficiency and low power consumption.In solid-state dielectrics,an electric field drives the redistribution o...Electric field control of magnetism through nanoionics has attracted tremendous attention owing to its high efficiency and low power consumption.In solid-state dielectrics,an electric field drives the redistribution of ions to create onedimensional magnetic conductive nanostructures,enabling the realization of intriguing magnetoresistance(MR)effects.Here,we explored the electric-controlled nickel and oxygen ion migration in Pt/HfO_(2-x)/NiO_(y)/Ni heterojunctions for MR modulation.By adjusting the voltage polarity and amplitude,the magnetic conductive filaments with mixed nickel and oxygen vacancy are constructed.This results in the reduction of device resistance by~10^(3)folds,and leads to an intriguing partial asymmetric MR effect.We show that the difference of the device resistance under positive and negative saturation magnetic fields exhibits good linear dependence on the magnetic field angle,which can be used for magnetic field direction detection.Our study suggests the potential of electrically controlled ion migration in creating novel magnetic nanostructures for sensor applications.展开更多
We fabricate SrRuO_(3)/PbZr_(0.52)Ti_(0.48)O_(3)heterostructures each with an in-plane tensile-strained SrRuO_(3)layer and investigate the effect of an applied electric field on anomalous Hall effect.The four-fold sym...We fabricate SrRuO_(3)/PbZr_(0.52)Ti_(0.48)O_(3)heterostructures each with an in-plane tensile-strained SrRuO_(3)layer and investigate the effect of an applied electric field on anomalous Hall effect.The four-fold symmetry of anisotropic magnetoresistance and the nonmonotonic variation of anomalous Hall resistivity are observed.By applying positive electric field or negative electric field,the intersecting hump-like feature is suppressed or enhanced,respectively.The sign and magnitude of the anomalous Hall conductivity can be effectively controlled with an electric field under a high magnetic field.The electric-field-modulated anomalous Hall effect is associated with the magnetization rotation in SrRuO_(3).The experimental results are helpful in modulating the magnetization rotation in spintronic devices based on SrRuO_(3)heterostructures.展开更多
Ni_(83)Fe_(17) films with a thickness of about 100 nm were deposited onthermal oxidized silicon substrates at ambient temperature, 240, 350, and 410℃ by DC magnetronsputtering. The deposition rate was about 0.11 nm/s...Ni_(83)Fe_(17) films with a thickness of about 100 nm were deposited onthermal oxidized silicon substrates at ambient temperature, 240, 350, and 410℃ by DC magnetronsputtering. The deposition rate was about 0.11 nm/s. The as-deposited films were annealed at 450,550, and 650℃, respectively, in a vacuum lower than 3 x 10~3 Pa for 1 h. The Ni_(83)Fe_(17) filmsmainly grow with a crystalline orientation of [111] in the direction of the film growth. With theannealing temperature increasing, the [111] orientation enhances. For films deposited at all fourdifferent temperatures, the significant improvement on anisotropic magnetoresistance occurs at theannealing temperature higher than 550℃. But for films deposited at ambient temperatures and 240 ℃,the anisotropic magnetoresistance can only rise to about 1% after 650 ℃ annealing. For filmsdeposited at 350℃ and 410℃, the anisotropic magnetoresistance rises to about 3.8% after 650℃annealing. The atomic force microscopy (AFM) observation shows a significant increase in grain sizeof the film deposited at 350℃ after 650℃ annealing. The decrease in resistivity and the increasein anisotropic magnetoresistance are caused by the decrease in point defects, the increase in grainsize, and the improvement in lattice structure integrity of the films.展开更多
Anisotropic magnetoresistance (AMR) is an important physical phenomenon that has broad application potential in many relevant fields. Thus, AMR is one of the most attractive research directions in material science t...Anisotropic magnetoresistance (AMR) is an important physical phenomenon that has broad application potential in many relevant fields. Thus, AMR is one of the most attractive research directions in material science to date. In this article, we summarize the recent advances in AMR, including traditional permalloy AMR, tunnel AMR, ballistic AMR, Coulomb blockade AMR, anomalous AMR, and antiferromagnetic AMR. The existing problems and possible challenges in developing more advanced AMR were briefly discussed, and future development trends and prospects were also speculated.展开更多
The magnetoresistance effect and magnetic properties in amorphous and nanocrystalline Fe(Cu, Nb)-Si-B ribbons have been investigated, it was observed that the anisotropic magnetoresistance (AMR) of nanocrystalline all...The magnetoresistance effect and magnetic properties in amorphous and nanocrystalline Fe(Cu, Nb)-Si-B ribbons have been investigated, it was observed that the anisotropic magnetoresistance (AMR) of nanocrystalline alloy is much smaller than that of amorphous alloy, Indicating that the anisotropy of nanocrystalline alloy becomes smaller after crystallizing, and the smallest AMR is coincident with the excellent soft magnetic characteristics. It is believed that the smaller magnetic crystalline anisotropy is the origin of the excellent soft magnetic characteristics of nanocrystalline alloy.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 report the observation of in-plane anisotropic magnetoresistance and planar Hall effect in non-magnetic HfTe_(5) thin layers.The observed anisotropic magnetoresistance as well as its sign is strongly dependent on t...We report the observation of in-plane anisotropic magnetoresistance and planar Hall effect in non-magnetic HfTe_(5) thin layers.The observed anisotropic magnetoresistance as well as its sign is strongly dependent on the critical resistivity anomaly temperature T_(p).Below T_(p),the anisotropic magnetoresistance is negative with large negative magnetoresistance.When the in-plane magnetic field is perpendicular to the current,the negative longitudinal magnetoresistance reaches its maximum.The negative longitudinal magnetoresistance effect in HfTe_(5) thin layers is dramatically different from that induced by the chiral anomaly as observed in Weyl and Dirac semimetals.One potential underlying origin may be attributed to the reduced spin scattering,which arises from the in-plane magnetic field driven coupling between the top and bottom surface states.Our findings provide valuable insights for the anisotropic magnetoresistance effect in topological electronic systems and the device potential of HfTe5 in spintronics and quantum sensing.展开更多
The anisotropic magnetoresistances(AMRs)in single crystalline Co(6 nm)/SrTiO_(3)(001)heterostructures from 5 K to 300 K with the current direction setting along either Co[100]or Co[110]are investigated in this work.Th...The anisotropic magnetoresistances(AMRs)in single crystalline Co(6 nm)/SrTiO_(3)(001)heterostructures from 5 K to 300 K with the current direction setting along either Co[100]or Co[110]are investigated in this work.The anomalous(normal)AMR is observed below(above)100 K.With the current along Co[100]direction,the AMR shows negative longitudinal and positive transverse magnetoresistances at T<100 K,while the AMR is inverse with the current along Co[110].Meanwhile,the amplitude ratio between Co[110]and Co[100]is observed to be as large as 29 at 100 K.A crystal symmetry-adapted model of AMR demonstrates that interplay between the non-crystalline component and crossed AMR component results in the anomalous AMR.Our results may reveal more intriguing magneto-transport behaviors of film on SrTiO_(3)or other perovskite oxides.展开更多
We study the coutrol of gate voltage over the magnetization of a single-molecule magnet (SMM) weakly coupled to a ferromagnetic and a normal metal electrode in the presence of the temperature gradient between two el...We study the coutrol of gate voltage over the magnetization of a single-molecule magnet (SMM) weakly coupled to a ferromagnetic and a normal metal electrode in the presence of the temperature gradient between two electrodes. It is demonstrated that the SMM's magnetization can change periodically with periodic gate voltage due to the driving oI the temperature gradient. Under an appropriate matching of the electrode polarization, the temperature difference and the pulse width of gate voltage, the SMM's magnetization can be completely reversed in a period of gate voltage. The corresponding flipping time can be controlled by the system parameters. In addition, we also investigate the tunneling anisotropic magnetoresistance (TAMFt) of the device in the steady state when the ferromagnetic electrode is noncollinear with the easy axis of the SMM, and show the jump characteristic of the TAMR.展开更多
High-quality Sr_(2)CrWO_(6)(SCWO) films have been grown on SrTiO_(3)(STO) substrate by pulsed laser deposition under low oxygen pressure. With decrease of the film thickness, a drastic conductivity increase is observe...High-quality Sr_(2)CrWO_(6)(SCWO) films have been grown on SrTiO_(3)(STO) substrate by pulsed laser deposition under low oxygen pressure. With decrease of the film thickness, a drastic conductivity increase is observed. The Hall measurements show that the thicker the film, the lower the carrier density. An extrinsic mechanism of charge doping due to the dominance of oxygen vacancies at SCWO/STO interfaces is proposed. The distribution and gradient of carrier concentration in SCWO films are considered to be related to this phenomenon. Resistivity behavior observed in these films is found to follow the variable range hopping model. It is revealed that with increase of the film thickness, the extent of disorder in the lattice increases, which gives a clear evidence of disorder-induced localization charge carriers in these films.Magnetoresistance measurements show that there is a negative magnetoresistance in SCWO films, which is considered to be caused by the magnetic scattering of magnetic elements Cr^(3+) and W^(5+). In addition, a sign reversal of anisotropic magnetoresistance(AMR) in SCWO film is observed for the first time, when the temperature varies across a characteristic value, T_(M). Magnetization-temperature measurements demonstrate that this AMR sign reversal is caused by the direction transition of easy axis of magnetization from the in-plane ferromagnetic order at T > T_(M) to the out-of-plane at T < T_(M).展开更多
A macroscopic model of the magnetoresistance effect in fimited anisotropic semiconductors is built. This model allows us to solve the problem of measurement of physical magnetoresistance components of crystals and fil...A macroscopic model of the magnetoresistance effect in fimited anisotropic semiconductors is built. This model allows us to solve the problem of measurement of physical magnetoresistance components of crystals and films. Based on a unified mathematical model the method is worked out enabling us to measure tensor components of the specific electrical resistance and the relative magnetoresistance of anisotropic semiconductors simultaneously.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFA1202600)the National Natural Science Foundation of China(Grant Nos.92064011,62174164,61974179,and 61674153)+3 种基金Youth Innovation Promotion Association of the CAS(Grant No.2020297)Natural Science Foundation of Zhejiang Province(Grant No.LR17E020001)Ningbo Natural Science Foundation(Grant No.202003N4029)C.Wong Education Foundation(Grant No.GJTD-2020-11)。
文摘Electric field control of magnetism through nanoionics has attracted tremendous attention owing to its high efficiency and low power consumption.In solid-state dielectrics,an electric field drives the redistribution of ions to create onedimensional magnetic conductive nanostructures,enabling the realization of intriguing magnetoresistance(MR)effects.Here,we explored the electric-controlled nickel and oxygen ion migration in Pt/HfO_(2-x)/NiO_(y)/Ni heterojunctions for MR modulation.By adjusting the voltage polarity and amplitude,the magnetic conductive filaments with mixed nickel and oxygen vacancy are constructed.This results in the reduction of device resistance by~10^(3)folds,and leads to an intriguing partial asymmetric MR effect.We show that the difference of the device resistance under positive and negative saturation magnetic fields exhibits good linear dependence on the magnetic field angle,which can be used for magnetic field direction detection.Our study suggests the potential of electrically controlled ion migration in creating novel magnetic nanostructures for sensor applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.11974099)the Intelligence Introduction Plan of Henan Province,China in 2021(Grant No.CXJD2021008)+1 种基金the Plan for Leading Talent of Fundamental Research of the Central China in 2020the Key Scientific Research Project of Colleges and Universities in Henan Province,China(Grant No.21A140005)。
文摘We fabricate SrRuO_(3)/PbZr_(0.52)Ti_(0.48)O_(3)heterostructures each with an in-plane tensile-strained SrRuO_(3)layer and investigate the effect of an applied electric field on anomalous Hall effect.The four-fold symmetry of anisotropic magnetoresistance and the nonmonotonic variation of anomalous Hall resistivity are observed.By applying positive electric field or negative electric field,the intersecting hump-like feature is suppressed or enhanced,respectively.The sign and magnitude of the anomalous Hall conductivity can be effectively controlled with an electric field under a high magnetic field.The electric-field-modulated anomalous Hall effect is associated with the magnetization rotation in SrRuO_(3).The experimental results are helpful in modulating the magnetization rotation in spintronic devices based on SrRuO_(3)heterostructures.
文摘Ni_(83)Fe_(17) films with a thickness of about 100 nm were deposited onthermal oxidized silicon substrates at ambient temperature, 240, 350, and 410℃ by DC magnetronsputtering. The deposition rate was about 0.11 nm/s. The as-deposited films were annealed at 450,550, and 650℃, respectively, in a vacuum lower than 3 x 10~3 Pa for 1 h. The Ni_(83)Fe_(17) filmsmainly grow with a crystalline orientation of [111] in the direction of the film growth. With theannealing temperature increasing, the [111] orientation enhances. For films deposited at all fourdifferent temperatures, the significant improvement on anisotropic magnetoresistance occurs at theannealing temperature higher than 550℃. But for films deposited at ambient temperatures and 240 ℃,the anisotropic magnetoresistance can only rise to about 1% after 650 ℃ annealing. For filmsdeposited at 350℃ and 410℃, the anisotropic magnetoresistance rises to about 3.8% after 650℃annealing. The atomic force microscopy (AFM) observation shows a significant increase in grain sizeof the film deposited at 350℃ after 650℃ annealing. The decrease in resistivity and the increasein anisotropic magnetoresistance are caused by the decrease in point defects, the increase in grainsize, and the improvement in lattice structure integrity of the films.
基金financially supported by the National Natural Science Foundation of China (Nos. 51071023 and 51101047)the Natural Science Foundation of Hainan Province (No. 512114)+1 种基金the Ph.D. Programs Foundation of Ministry of Education (No. 20120006130002)Program for Changjiang Scholars and Innovative Research Team in University
文摘Anisotropic magnetoresistance (AMR) is an important physical phenomenon that has broad application potential in many relevant fields. Thus, AMR is one of the most attractive research directions in material science to date. In this article, we summarize the recent advances in AMR, including traditional permalloy AMR, tunnel AMR, ballistic AMR, Coulomb blockade AMR, anomalous AMR, and antiferromagnetic AMR. The existing problems and possible challenges in developing more advanced AMR were briefly discussed, and future development trends and prospects were also speculated.
基金Natural Science Foundation of Liaoning Province!(No. 972812).
文摘The magnetoresistance effect and magnetic properties in amorphous and nanocrystalline Fe(Cu, Nb)-Si-B ribbons have been investigated, it was observed that the anisotropic magnetoresistance (AMR) of nanocrystalline alloy is much smaller than that of amorphous alloy, Indicating that the anisotropy of nanocrystalline alloy becomes smaller after crystallizing, and the smallest AMR is coincident with the excellent soft magnetic characteristics. It is believed that the smaller magnetic crystalline anisotropy is the origin of the excellent soft magnetic characteristics of nanocrystalline alloy.
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 Key R&D Program(Grant Nos.2017YFB0405703,2017YFA0205004,and 2018YFA0306600)the National Natural Science Foundation of China(Grant Nos.11974327,11474265,11674295,11674024,and 11874193)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.WK2030020032 and WK2340000082)Anhui Initiative in Quantum Information Technologies,and the Shenzhen Fundamental Subject Research Program(Grant No.JCYJ20170817110751776)the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘We report the observation of in-plane anisotropic magnetoresistance and planar Hall effect in non-magnetic HfTe_(5) thin layers.The observed anisotropic magnetoresistance as well as its sign is strongly dependent on the critical resistivity anomaly temperature T_(p).Below T_(p),the anisotropic magnetoresistance is negative with large negative magnetoresistance.When the in-plane magnetic field is perpendicular to the current,the negative longitudinal magnetoresistance reaches its maximum.The negative longitudinal magnetoresistance effect in HfTe_(5) thin layers is dramatically different from that induced by the chiral anomaly as observed in Weyl and Dirac semimetals.One potential underlying origin may be attributed to the reduced spin scattering,which arises from the in-plane magnetic field driven coupling between the top and bottom surface states.Our findings provide valuable insights for the anisotropic magnetoresistance effect in topological electronic systems and the device potential of HfTe5 in spintronics and quantum sensing.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174163 and 91963201)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT-16R35)the 111 Project,China(Grant No.B20063)。
文摘The anisotropic magnetoresistances(AMRs)in single crystalline Co(6 nm)/SrTiO_(3)(001)heterostructures from 5 K to 300 K with the current direction setting along either Co[100]or Co[110]are investigated in this work.The anomalous(normal)AMR is observed below(above)100 K.With the current along Co[100]direction,the AMR shows negative longitudinal and positive transverse magnetoresistances at T<100 K,while the AMR is inverse with the current along Co[110].Meanwhile,the amplitude ratio between Co[110]and Co[100]is observed to be as large as 29 at 100 K.A crystal symmetry-adapted model of AMR demonstrates that interplay between the non-crystalline component and crossed AMR component results in the anomalous AMR.Our results may reveal more intriguing magneto-transport behaviors of film on SrTiO_(3)or other perovskite oxides.
基金Supported by the National Natural Science Foundation of China under Grant No 11274208
文摘We study the coutrol of gate voltage over the magnetization of a single-molecule magnet (SMM) weakly coupled to a ferromagnetic and a normal metal electrode in the presence of the temperature gradient between two electrodes. It is demonstrated that the SMM's magnetization can change periodically with periodic gate voltage due to the driving oI the temperature gradient. Under an appropriate matching of the electrode polarization, the temperature difference and the pulse width of gate voltage, the SMM's magnetization can be completely reversed in a period of gate voltage. The corresponding flipping time can be controlled by the system parameters. In addition, we also investigate the tunneling anisotropic magnetoresistance (TAMFt) of the device in the steady state when the ferromagnetic electrode is noncollinear with the easy axis of the SMM, and show the jump characteristic of the TAMR.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 92065110, 11974048, and 12074334)。
文摘High-quality Sr_(2)CrWO_(6)(SCWO) films have been grown on SrTiO_(3)(STO) substrate by pulsed laser deposition under low oxygen pressure. With decrease of the film thickness, a drastic conductivity increase is observed. The Hall measurements show that the thicker the film, the lower the carrier density. An extrinsic mechanism of charge doping due to the dominance of oxygen vacancies at SCWO/STO interfaces is proposed. The distribution and gradient of carrier concentration in SCWO films are considered to be related to this phenomenon. Resistivity behavior observed in these films is found to follow the variable range hopping model. It is revealed that with increase of the film thickness, the extent of disorder in the lattice increases, which gives a clear evidence of disorder-induced localization charge carriers in these films.Magnetoresistance measurements show that there is a negative magnetoresistance in SCWO films, which is considered to be caused by the magnetic scattering of magnetic elements Cr^(3+) and W^(5+). In addition, a sign reversal of anisotropic magnetoresistance(AMR) in SCWO film is observed for the first time, when the temperature varies across a characteristic value, T_(M). Magnetization-temperature measurements demonstrate that this AMR sign reversal is caused by the direction transition of easy axis of magnetization from the in-plane ferromagnetic order at T > T_(M) to the out-of-plane at T < T_(M).
文摘A macroscopic model of the magnetoresistance effect in fimited anisotropic semiconductors is built. This model allows us to solve the problem of measurement of physical magnetoresistance components of crystals and films. Based on a unified mathematical model the method is worked out enabling us to measure tensor components of the specific electrical resistance and the relative magnetoresistance of anisotropic semiconductors simultaneously.