Author Affiliations
Abstract
1 Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2 School of Physics, University of Chinese Academy of Sciences, Beijing 100190, China
We report the study of magnetic and transport properties of polycrystalline and single crystal Na(Zn,Mn)Sb, a new member of “111” type of diluted magnetic materials. The material crystallizes into Cu2Sb-type structure which is isostructural to “111” type Fe-based superconductors. With suitable carrier and spin doping, the Na(Zn,Mn)Sb establishes spin-glass ordering with freezing temperature (Tf) below 15 K. Despite lack of long-range ferromagnetic ordering, Na(Zn,Mn)Sb single crystal still shows sizeable anomalous Hall effect belowTf. Carrier concentration determined by Hall effect measurements is over 1019 cm–3. More significantly, we observe colossal negative magnetoresistance (MR ≡ [ρ(H) ? ρ(0)]/ρ(0)) of –94% in the single crystal sample.We report the study of magnetic and transport properties of polycrystalline and single crystal Na(Zn,Mn)Sb, a new member of “111” type of diluted magnetic materials. The material crystallizes into Cu2Sb-type structure which is isostructural to “111” type Fe-based superconductors. With suitable carrier and spin doping, the Na(Zn,Mn)Sb establishes spin-glass ordering with freezing temperature (Tf) below 15 K. Despite lack of long-range ferromagnetic ordering, Na(Zn,Mn)Sb single crystal still shows sizeable anomalous Hall effect belowTf. Carrier concentration determined by Hall effect measurements is over 1019 cm–3. More significantly, we observe colossal negative magnetoresistance (MR ≡ [ρ(H) ? ρ(0)]/ρ(0)) of –94% in the single crystal sample.
colossal negative magnetoresistance spin glass diluted magnetic materials Journal of Semiconductors
2023, 44(3): 032501
新疆大学 物理科学与技术学院, 乌鲁木齐 830046
尺寸小、均匀单分散的MnFe2O4在生物材料、隐身技术、磁流体和锂电池等领域具有巨大的应用潜力。文章采用多元醇混合水热法, 以氯化锰(MnCl2·6H2O)、硝酸铁[Fe(NO)3·6H2O]作为原料, 以氢氧化钠(NaOH)为矿化剂, TERG作为分散剂, 制备出了均匀单分散的MnFe2O4纳米磁性粉体。通过改变反应时间, 实现了纳米颗粒的尺寸可控制备。采用XRD、TEM和VSM等手段对制备的纳米磁性材料进行表征。实验结果表明, TREG对MnFe2O4纳米颗粒起到了分散作用, 随着MnFe2O4纳米磁性颗粒尺寸的减小, 其饱和磁化强度、矫顽力均减小, 禁带宽度变大, 光吸收能力增强, 而且当尺寸为5nm时, 出现特征吸收下降现象。
锰铁氧体 水热法 磁性材料 MnFe2O4 MnFe2O4 manganese ferrite hydrothermal magnetic materials
1 西南科技大学 材料科学与工程学院, 四川 绵阳 621010
2 中国工程物理研究院 激光聚变研究中心, 四川 绵阳 621900
采用电弧式熔体快淬/吸铸技术, 制备了不同成分的Ni-Nd-B试样, 借助X射线衍射、扫描电子显微镜、热分析法、静态磁性测试仪等手段进行了分析。研究发现, 用电弧式熔体快淬/吸铸技术可以较成功制备系列直径6 mm的Ni-Nd-B大块非晶, 且满足深度共晶成分试样表, 表现出较理想的非晶形成能力。Ni4NdB材料具有约79.13 ℃的过冷度, Ni13Nd3B2材料具有约69.37 ℃的过冷度；Ni, Nd成分微量变化引起材料较明显的晶化趋向。此外, Ni, Nd成分微量变化导致材料矫顽力、饱和磁化强度减小。
Ni基非晶 电弧熔炼 稀土过渡金属间化合物 磁性材料 过冷度 Ni-based amorphous material arc melting rare earth-transition metal compound magnetic materials undercooling temperature
