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    Structural, magnetic properties, and electronic structure of hexagonal FeCoSn compound
    Yong Li(李勇), Xue-Fang Dai(代学芳), Guo-Dong Liu(刘国栋), Zhi-Yang Wei(魏志阳), En-Ke Liu(刘恩克), Xiao-Lei Han(韩小磊), Zhi-Wei Du(杜志伟), Xue-Kui Xi(郗学奎), Wen-Hong Wang(王文洪), Guang-Heng Wu(吴光恒)
    Chin. Phys. B, 2018, 27 (2): 026101.   DOI: 10.1088/1674-1056/27/2/026101
    Abstract322)   HTML    PDF (2156KB)(275)      

    The structural, magnetic properties, and electronic structures of hexagonal FeCoSn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscope (TEM), scanning electron microscope (SEM), magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe (1 Oe=79.5775 A·m-1). The orbital hybridizations between 3d elements are analyzed from the distribution of density of states (DOS), showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.

    Growth and transport properties of topological insulator Bi2Se3 thin film on a ferromagnetic insulating substrate
    Shanna Zhu(朱珊娜), Gang Shi(史刚), Peng Zhao(赵鹏), Dechao Meng(孟德超), Genhao Liang(梁根豪), Xiaofang Zhai(翟晓芳), Yalin Lu(陆亚林), Yongqing Li(李永庆), Lan Chen(陈岚), Kehui Wu(吴克辉)
    Chin. Phys. B, 2018, 27 (7): 076801.   DOI: 10.1088/1674-1056/27/7/076801
    Abstract251)   HTML    PDF (2358KB)(185)      

    Exchange coupling between topological insulator and ferromagnetic insulator through proximity effect is strongly attractive for both fundamental physics and technological applications. Here we report a comprehensive investigation on the growth behaviors of prototype topological insulator Bi2Se3 thin film on a single-crystalline LaCoO3 thin film on SrTiO3 substrate, which is a strain-induced ferromagnetic insulator. Different from the growth on other substrates, the Bi2Se3 films with highest quality on LaCoO3 favor a relatively low substrate temperature during growth. As a result, an inverse dependence of carrier mobility with the substrate temperature is found. Moreover, the magnetoresistance and coherence length of weak antilocalization also have a similar inverse dependence with the substrate temperature, as revealed by the magnetotransport measurements. Our experiments elucidate the special behaviors in Bi2Se3/LaCoO3 heterostructures, which provide a good platform for exploring related novel quantum phenomena, and are inspiring for device applications.

    Magnetocaloric effect in the layered organic-inorganic hybrid (CH3NH3)2CuCl4
    Yinina Ma(马怡妮娜), Kun Zhai(翟昆), Liqin Yan(闫丽琴), Yisheng Chai(柴一晟), Dashan Shang(尚大山), Young Sun(孙阳)
    Chin. Phys. B, 2018, 27 (2): 027501.   DOI: 10.1088/1674-1056/27/2/027501
    Abstract457)   HTML    PDF (815KB)(354)      

    We present a study of magnetocaloric effect of the quasi-two-dimensional (2D) ferromagnet (CH3NH3)2CuCl4 in ab plane (easy-plane). From the measurements of magnetic field dependence of magnetization at various temperatures, we have discovered a large magnetic entropy change associated with the ferromagnetic-paramagnetic transition. The heat capacity measurements reveal an abnormal adiabatic change below the Curie temperature Tc~8.9 K, which is caused by the nature of quasi-2D layered crystal structure. These results suggest that perovskite organic-inorganic hybrids with a layered structure are suitable candidates as working substances in magnetic refrigeration technology.

    Spin-independent transparency of pure spin current at normal/ferromagnetic metal interface
    Runrun Hao(郝润润), Hai Zhong(钟海), Yun Kang(康韵), Yufei Tian(田雨霏), Shishen Yan(颜世申), Guolei Liu(刘国磊), Guangbing Han(韩广兵), Shuyun Yu(于淑云), Liangmo Mei(梅良模), Shishou Kang(康仕寿)
    Chin. Phys. B, 2018, 27 (3): 037202.   DOI: 10.1088/1674-1056/27/3/037202
    Abstract293)   HTML    PDF (827KB)(171)      

    The spin transparency at the normal/ferromagnetic metal (NM/FM) interface was studied in Pt/YIG/Cu/FM multilayers. The spin current generated by the spin Hall effect (SHE) in Pt flows into Cu/FM due to magnetic insulator YIG blocking charge current and transmitting spin current via the magnon current. Therefore, the nonlocal voltage induced by an inverse spin Hall effect (ISHE) in FM can be detected. With the magnetization of FM parallel or antiparallel to the spin polarization of pure spin currents (σsc), the spin-independent nonlocal voltage is induced. This indicates that the spin transparency at the Cu/FM interface is spin-independent, which demonstrates that the influence of spin-dependent electrochemical potential due to spin accumulation on the interfacial spin transparency is negligible. Furthermore, a larger spin Hall angle of Fe20Ni80 (Py) than that of Ni is obtained from the nonlocal voltage measurements.

    Unusual tunability of multiferroicity in GdMn2O5 by electric field poling far above multiferroic ordering point
    Xiang Li(李翔), Shuhan Zheng(郑书翰), Liman Tian(田礼漫), Rui Shi(石锐), Meifeng Liu(刘美风), Yunlong Xie(谢云龙), Lun Yang(杨伦), Nian Zhao(赵念), Lin Lin(林林), Zhibo Yan(颜志波), Xiuzhang Wang(王秀章), Junming Liu(刘俊明)
    Chin. Phys. B, 2019, 28 (2): 027502.   DOI: 10.1088/1674-1056/28/2/027502
    Abstract332)   HTML    PDF (1067KB)(227)      

    The multiferroicity in the RMn2O5 family remains unclear, and less attention has been paid to its dependence on high-temperature (high-T) polarized configuration. Moreover, no consensus on the high-T space group symmetry has been reached so far. In view of this consideration, one may argue that the multiferroicity of RMn2O5 in the low-T range depends on the poling sequence starting far above the multiferroic ordering temperature. In this work, we investigate in detail the variation of magnetically induced electric polarization in GdMn2O5 and its dependence on electric field poling routine in the high-T range. It is revealed that the multiferroicity does exhibit qualitatively different behaviors if the high-T poling routine changes, indicating the close correlation with the possible high-T polarized state. These emergent phenomena may be qualitatively explained by the co-existence of two low-T polarization components, a scenario that was proposed earlier. One is the component associated with the Mn3+-Mn4+-Mn3+ exchange striction that seems to be tightly clamped by the high-T polarized state, and the other is the component associated with the Gd3+-Mn4+-Gd3+ exchange striction that is free of the clamping. The present findings may offer a different scheme for the electric control of the multiferroicity in RMn2O5.

    Antiferromagnetic interlayer coupling of (111)-oriented La0.67Sr0.33MnO3/SrRuO3 superlattices
    Hui Zhang(张慧), Jing Zhang(张静), Jin-E Zhang(张金娥), Fu-Rong Han(韩福荣), Hai-Lin Huang(黄海林), Jing-Hua Song(宋京华), Bao-Gen Shen(沈保根), Ji-Rong Sun(孙继荣)
    Chin. Phys. B, 2019, 28 (3): 037501.   DOI: 10.1088/1674-1056/28/3/037501
    Abstract263)   HTML    PDF (773KB)(163)      

    We report a strong antiferromagnetic (AFM) interlayer coupling in ferromagnetic La0.67Sr0.33MnO3/SrRuO3 (LSMO/SRO) superlattices grown on (111)-oriented SrTiO3 substrate. Unlike the (001) superlattices for which the spin alignment between LSMO and SRO is antiparallel in the in-plane direction and parallel in the out-of-plane direction, the antiparallel alignment is observed along both the in-plane and out-of-plane directions in the present sample. The low temperature hysteresis loop demonstrates two-step magnetic processes, indicating the coexistence of magnetically soft and hard components. Moreover, an inverted hysteresis loop was observed. Exchange bias tuned by the temperature and cooling field was also investigated, and positive as well as negative exchange bias was observed at the same temperature with the variation of the cooling field. A very large exchange field (HEB) was observed and both magnitude and sign of the HEB depend on the cooling field, which can be attributed to an interplay of Zeeman energy and AFM coupling energy at the interfaces. The present work shows the great potential of tuning a spin texture through interfacial engineering for the complex oxides whose spin state is jointly determined by strongly competing mechanisms.

    Micromagnetic simulations of reversal magnetization in cerium-containing magnets
    Lei Li(李磊), Shengzhi Dong(董生智), Hongsheng Chen(陈红升), Ruijiao Jiang(姜瑞姣), Dong Li(李栋), Rui Han(韩瑞), Dong Zhou(周栋), Minggang Zhu(朱明刚), Wei Li(李卫), Wei Sun(孙威)
    Chin. Phys. B, 2019, 28 (3): 037502.   DOI: 10.1088/1674-1056/28/3/037502
    Abstract278)   HTML    PDF (1476KB)(145)      

    Single-grain models with different cerium contents or structural parameters have been introduced to investigate the reversal magnetization behaviors in cerium-containing magnets. All the micromagnetic simulations are carried out via the object oriented micromagnetic framework (OOMMF). As for single (Nd,Ce)2Fe14B type grain, the coercivity decreases monotonously with the increase of the cerium content. Four types of grain structure have been compared:single (Nd,Ce)2Fe14B type, core ((Nd,Ce)2Fe14B)-shell (Nd2Fe14B) type with 2 nm thick shell, core (Ce2Fe14B)-shell (Nd2Fe14B) type, and core (Nd2Fe14B)-shell (Ce2Fe14B) type. It is found that core ((Nd,Ce)2Fe14B)-shell (Nd2Fe14B) type grain with 2 nm thick shell always presents the largest coercivity under the same total cerium content. Furthermore, the relationship between the coercivity and the shell thickness t in core ((Nd,Ce)2Fe14B)-shell (Nd2Fe14B) type grain has been studied. When the total cerium content is kept at 20.51 at.%, the analyzed results show that as t varies from 1 nm to 7 nm, the coercivity gradually ascends at the beginning, then quickly descends after reaching the maximum value when t=5 nm. From the perspective of the positions of nucleation points, the reasons why t affects the coercivity are discussed in detail.

    Raman scattering study of magnetic layered MPS3 crystals (M=Mn, Fe, Ni)
    Yi-Meng Wang(王艺朦), Jian-Feng Zhang(张建丰), Cheng-He Li(李承贺), Xiao-Li Ma(马肖莉), Jian-Ting Ji(籍建葶), Feng Jin(金峰), He-Chang Lei(雷和畅), Kai Liu(刘凯), Wei-Lu Zhang(张玮璐), Qing-Ming Zhang(张清明)
    Chin. Phys. B, 2019, 28 (5): 056301.   DOI: 10.1088/1674-1056/28/5/056301
    Abstract374)   HTML    PDF (1176KB)(332)      

    We report a comprehensive Raman scattering study on layered MPS3 (M=Mn, Fe, Ni), a two-dimensional magnetic compound with weak van der Waals interlayer coupling. The observed Raman phonon modes have been well assigned by the combination of first-principles calculations and the polarization-resolved spectra. Careful symmetry analysis on the angle-dependent spectra demonstrates that the crystal symmetry is strictly described by C2h but can be simplified to D3d with good accuracy. Interestingly, the three compounds share exactly the same lattice structure but show distinct magnetic structures. This provides us with a unique opportunity to study the effect of different magnetic orders on lattice dynamics in MPS3. Our results reveal that the in-plane Néel antiferromagnetic (AF) order in MnPS3 favors a spin-phonon coupling compared to the in-plane zig-zag AF in NiPS3 and FePS3. We have discussed the mechanism in terms of the folding of magnetic Brillouin zones. Our results provide insights into the relation between lattice dynamics and magnetism in the layered MPX3 (M=transition metal, X=S, Se) family and shed light on the magnetism of monolayer MPX3 materials.

    Effects of chemical pressure on diluted magnetic semiconductor (Ba,K)(Zn,Mn)2As2
    Y Peng(彭毅), S Yu(于爽), G Q Zhao(赵国强), W M Li(李文敏), J F Zhao(赵建发), L P Cao(曹立朋), X C Wang(望贤成), Q Q Liu(刘清青), S J Zhang(张思佳), R Z Yu(于润泽), Z Deng(邓正), X H Zhu(朱小红), C Q Jin(靳常青)
    Chin. Phys. B, 2019, 28 (5): 057501.   DOI: 10.1088/1674-1056/28/5/057501
    Abstract220)   HTML    PDF (1330KB)(232)      

    Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor (Ba,K)(Zn,Mn)2As2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively. X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-under-doped and K-optimal-doped samples are effectively tuned by Sb- and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb- and P-doping. Impressively, magnetoresistance is significantly improved from 7% to 27% by only 10% P-doping, successfully extending potential application of (Ba,K)(Zn,Mn)2As2.

    Computational study of inverse ferrite spinels
    A EL Maazouzi, R Masrour, A Jabar, M Hamedoun
    Chin. Phys. B, 2019, 28 (5): 057504.   DOI: 10.1088/1674-1056/28/5/057504
    Abstract181)   HTML    PDF (520KB)(153)      

    The magnetic properties of inverse ferrite (Fe3+) [Fe3+Co2+]O42-,(Fe3+) [Fe3+Cu2+]O42-,(Fe3+) [Fe3+Fe2+]O42-, and (Fe3+) [Fe3+Ni2+]O42- spinels have been studied using Monte Carlo simulation. We have also calculated the critical and Curie Weiss temperatures from the thermal magnetizations and inverse of magnetic susceptibilities for each system. Magnetic hysteresis cycles have been found for the four systems. Finally, we found the critical exponents associated with magnetization, magnetic susceptibility, and external magnetic field. Our results of critical and Curie Weiss temperatures are similar to those obtained by experiment results. The critical exponents are similar to those of known 3D-Ising model.

    Magnetization-direction-dependent inverse spin Hall effect observed in IrMn/NiFe/Cu/YIG multilayer structure
    Runrun Hao(郝润润), Ruxue Zang(臧如雪), Tie Zhou(周铁), Shishou Kang(康仕寿), Shishen Yan(颜世申), Guolei Liu(刘国磊), Guangbing Han(韩广兵), Shuyun Yu(于淑云), Liangmo Mei(梅良模)
    Chin. Phys. B, 2019, 28 (3): 037202.   DOI: 10.1088/1674-1056/28/3/037202
    Abstract255)   HTML    PDF (1501KB)(138)      

    The magnetization-direction-dependent inverse spin Hall effect (ISHE) has been observed in NiFe film during spin Seebeck measurement in IrMn/NiFe/Cu/yttrium iron garnet (YIG) multilayer structure, where the YIG and NiFe layers act as the spin injector and spin current detector, respectively. By using the NiFe/IrMn exchange bias structure, the magnetization direction of YIG (MYIG) can be rotated with respect to that of NiFe (MNiFe) with a small magnetic field, thus allowing us to observe the magnetization-direction-dependent inverse spin Hall effect voltage in NiFe layer. Compared with the situation that polarization direction of spin current (σs) is perpendicular to MNiFe, the spin Seebeck voltage is about 30% larger than that when σs and MNiFe are parallel to each other. This phenomenon may originate from either or both of stronger interface or bulk scattering to spin current when σs and MNiFe are perpendicular to each other. Our work provides a way to control the voltage induced by ISHE in ferromagnets.

    Spin torque nano-oscillators with a perpendicular spin polarizer
    Cuixiu Zheng(郑翠秀), Hao-Hsau Chen(陈浩轩), Xiangli Zhang(张祥丽), Zongzhi Zhang(张宗芝), Yaowen Liu(刘要稳)
    Chin. Phys. B, 2019, 28 (3): 037503.   DOI: 10.1088/1674-1056/28/3/037503
    Abstract362)   HTML    PDF (1704KB)(194)      
    We present an overview in the understanding of spin-transfer torque (STT) induced magnetization dynamics in spin-torque nano-oscillator (STNO) devices. The STNO contains an in-plane (IP) magnetized free layer and an out-of-plane (OP) magnetized spin polarizing layer. After a brief introduction, we first use mesoscopic micromagnetic simulations, which are based on the Landau-Lifshitz-Gilbert equation including the STT effect, to specify how a spin-torque term may tune the magnetization precession orbits of the free layer, showing that the oscillator frequency is proportional to the current density and the z-component of the free layer magnetization. Next, we propose a pendulum-like model within the macrospin approximation to describe the dynamic properties in such type of STNOs. After that, we further show the procession dynamics of the STNOs excited by IP and OP dual spin-polarizers. Both the numerical simulations and analytical theory indicate that the precession frequency is linearly proportional to the spin-torque of the OP polarizer only and is irrelevant to the spin-torque of the IP polarizer. Finally, a promising approach of coordinate transformation from the laboratory frame to the rotation frame is introduced, by which the nonstationary OP magnetization precession process is therefore transformed into the stationary process in the rotation frame. Through this method, a promising digital frequency shift-key modulation technique is presented, in which the magnetization precession can be well controlled at a given orbit as well as its precession frequency can be tuned with the co-action of spin polarized current and magnetic field (or electric field) pulses.
    Crystallographic and magnetic properties of van der Waals layered FePS3 crystal
    Qi-Yun Xie(解其云), Min Wu(吴敏), Li-Min Chen(陈丽敏), Gang Bai(白刚), Wen-Qin Zou(邹文琴), Wei Wang(王伟), Liang He(何亮)
    Chin. Phys. B, 2019, 28 (5): 056102.   DOI: 10.1088/1674-1056/28/5/056102
    Abstract241)   HTML    PDF (1154KB)(287)      

    The crystallographic and magnetic properties are presented for van der Waals antiferromagnetic FePS3. High-quality single crystals of millimeter size have been successfully synthesized through the chemical vapor transport method. The layered structure and cleavability of the compound are apparent, which are beneficial for a potential exploration of the interesting low dimensional magnetism, as well as for incorporation of FePS3 into van der Waals heterostructures. For the sake of completeness, we have measured both direct current (dc) and alternating current (ac) magnetic susceptibility. The paramagnetic to antiferromagnetic transition occurs at approximately TN~115 K. The effective moment is larger than the spin-only effective moment, suggesting that an orbital contribution to the total angular momentum of the Fe2+ could be present. The ac susceptibility is independent of frequency, which means that the spin freezing effect is excluded. Strong anisotropy of out-of-plane and in-plane susceptibility has been shown, demonstrating the Ising-type magnetic order in FePS3 system.

    Critical behavior and magnetocaloric effect in magnetic Weyl semimetal candidate Co2-xZrSn
    Tianlin Yu(于天麟), Xiaoyun Yu(余骁昀), En Yang(杨恩), Chang Sun(孙畅), Xiao Zhang(张晓), Ming Lei(雷鸣)
    Chin. Phys. B, 2019, 28 (6): 067501.   DOI: 10.1088/1674-1056/28/6/067501
    Abstract227)   HTML    PDF (808KB)(180)      

    We investigate the critical exponents and magnetocaloric effect of Co2-xZrSn polycrystal. The Co2-xZrSn undergoes a second-order ferromagnetism phase transition around the Curie temperature of Tc~280 K. The critical behavior in the vicinity of the magnetic phase transition has been investigated by using modified Arrott plot and Kouvel-Fisher methods. The obtained critical exponents, β, γ, and δ can be well described by the scaling theory. The determined exponents of Co2-xZrSn obey the mean-field model with a long-range magnetic interaction. In addition, the maximum magnetic entropy change -ΔSMmax of Co2-xZrSn is about 0.57 J·kg-1·K-1 and the relative cooling power (RCP) is 14.68 J·kg-1 at 50 kOe (1 Oe=79.5775 A·m-1).

    Spin glassy behavior and large exchange bias effect in cubic perovskite Ba0.8Sr0.2FeO3-δ
    Yu-Xuan Liu(刘宇轩), Zhe-Hong Liu(刘哲宏), Xu-Bin Ye(叶旭斌), Xu-Dong Shen(申旭东), Xiao Wang(王潇), Bo-Wen Zhou(周博文), Guang-Hui Zhou(周光辉), You-Wen Long(龙有文)
    Chin. Phys. B, 2019, 28 (6): 068104.   DOI: 10.1088/1674-1056/28/6/068104
    Abstract225)   HTML    PDF (1770KB)(161)      

    A single-phase iron oxide Ba0.8Sr0.2FeO3-δ with a simple cubic perovskite structure in Pm-3m symmetry is successfully synthesized by a solid-state reaction method in O2 flow. The oxygen content is determined to be about 2.81, indicating the formation of mixed Fe3+ and Fe4+ charge states with a disorder fashion. As a result, the compound shows small-polaron conductivity behavior, as well as spin glassy features arising from the competition between the ferromagnetic interaction and the antiferromagnetic interaction. Moreover, the competing interactions also give rise to a remarkable exchange bias effect in Ba0.8Sr0.2FeO2.81, providing an opportunity to use it in spin devices.

    Electronic and magnetic properties of CrI3 nanoribbons and nanotubes
    Ji-Zhang Wang(王吉章), Jian-Qi Huang(黄建啟), Ya-Ning Wang(王雅宁), Teng Yang(杨腾), Zhi-Dong Zhang(张志东)
    Chin. Phys. B, 2019, 28 (7): 077301.   DOI: 10.1088/1674-1056/28/7/077301
    Abstract252)   HTML    PDF (3160KB)(271)      

    CrI3 in two-dimensional (2D) forms has been attracting much attention lately due to its novel magnetic properties at atomic large scale. The size and edge tuning of electronic and magnetic properties for 2D materials has been a promising way to broaden or even enhance their utility, as the case with nanoribbons/nanotubes in graphene, black phosphorus, and transition metal dichalcogenides. Here we studied the CrI3 nanoribbon (NR) and nanotube (NT) systematically to seek the possible size and edge control of the electronic and magnetic properties. We find that ferromagnetic ordering is stable in all the NR and NT structures of interest. An enhancement of the Curie temperature TC can be expected when the structure goes to NR or NT from its 2D counterpart. The energy difference between the FM and AFM states can be even improved by up to 3-4 times in a zigzag nanoribbon (ZZNR), largely because of the electronic instability arising from a large density of states of iodine-5p orbitals at EF. In NT structures, shrinking the tube size harvests an enhancement of spin moment by up to 4%, due to the reduced crystal-field gap and the re-balance between the spin majority and minority populations.

    Spin transport in antiferromagnetic insulators
    Zhiyong Qiu(邱志勇), Dazhi Hou(侯达之)
    Chin. Phys. B, 2019, 28 (8): 088504.   DOI: 10.1088/1674-1056/28/8/088504
    Abstract358)   HTML    PDF (3095KB)(466)      
    Electrical spin, which is the key element of spintronics, has been regarded as a powerful substitute for the electrical charge in the next generation of information technology, in which spin plays the role of the carrier of information and/or energy in a similar way to the electrical charge in electronics. Spin-transport phenomena in different materials are central topics of spintronics. Unlike electrical charge, spin transport does not depend on electron motion, particularly spin can be transported in insulators without accompanying Joule heating. Therefore, insulators are considered to be ideal materials for spin conductors, in which magnetic insulators are the most compelling systems. Recently, we experimentally studied and theoretically discussed spin transport in various antiferromagnetic systems and identified spin susceptibility and the Néel vector as the most important factors for spin transport in antiferromagnetic systems. Herein, we summarize our experimental results, physical nature, and puzzles unknown. Further challenges and potential applications are also discussed.
    Visualization of tunnel magnetoresistance effect in single manganite nanowires
    Yang Yu(郁扬), Wenjie Hu(胡雯婕), Qiang Li(李强), Qian Shi(时倩), Yinyan Zhu(朱银燕), Hanxuan Lin(林汉轩), Tian Miao(苗田), Yu Bai(白羽), Yanmei Wang(王艳梅), Wenting Yang(杨文婷), Wenbin Wang(王文彬), Hangwen Guo(郭杭闻), Lifeng Yin(殷立峰), Jian Shen(沈健)
    Chin. Phys. B, 2020, 29 (1): 018501.   DOI: 10.1088/1674-1056/ab5932
    Abstract318)   HTML    PDF (675KB)(165)      
    We reported a study of tunnel magnetoresistance (TMR) effect in single manganite nanowire via the combination of magnetotransport and magnetic force microscopy imaging. TMR value up to 290% has been observed in single (La1-yPry)1-xCaxMnO3 nanowires with varying width. We find that the TMR effect can be explained in the scenario of opening and blockade of conducting channels from inherent magnetic domain evolutions. Our findings provide a new route to fabricate TMR junctions and point towards future improvements in complex oxide-based TMR spintronics.
    Giant topological Hall effect of ferromagnetic kagome metal Fe3Sn2
    Qi Wang(王琦), Qiangwei Yin(殷蔷薇), Hechang Lei(雷和畅)
    Chin. Phys. B, 2020, 29 (1): 017101.   DOI: 10.1088/1674-1056/ab5fbc
    Abstract456)   HTML    PDF (671KB)(544)      
    We present the experiment observation of a giant topological Hall effect (THE) in a frustrated kagome bilayer magnet Fe3Sn2. The negative topologically Hall resistivity appears when the field is below 1.3 T and it increases with increasing temperature up to 300 K. Its maximum absolute value reaches ~2.01 μΩ·cm at 300 K and 0.76 T. The origins of the observed giant THE can be attributed to the coexistence of the field-induced skyrmion state and the non-collinear spin configuration, possibly related to the magnetic frustration interaction in Fe3Sn2.
    Quaternary antiferromagnetic Ba2BiFeS5 with isolated FeS4 tetrahedra
    Shaohua Wang(王少华), Xiao Zhang(张晓), Hechang Lei(雷和畅)
    Chin. Phys. B, 2019, 28 (8): 087401.   DOI: 10.1088/1674-1056/28/8/087401
    Abstract184)   HTML    PDF (2515KB)(154)      

    We report the detailed physical properties of quaternary compound Ba2BiFeS5 with the key structural ingredient of isolated FeS4 tetrahedra. Magnetization and heat capacity measurements clearly indicate that Ba2BiFeS5 has a paramagnetic to antiferromagnetic transition at about 30 K. The calculated magnetic entropy above ordering temperature is much smaller than theoretical value for high-spin Fe3+ ion with S=5/2, implying the possible short-range antiferromagnetic fluctuation in Ba2BiFeS5.