Journal of Solid State Chemistry ( IF 3.2 ) Pub Date : 2020-01-16 , DOI: 10.1016/j.jssc.2020.121188 Jiro Kitagawa , Genta Yakabe , Akinori Nakayama , Terukazu Nishizaki , Masami Tsubota
Polycrystalline Al7+xFe23Ge14−x-type orthorhombic Al8.5−xFe23Ge12.5+x (0 ≤ x≤3) compounds were studied by X-ray diffraction measurement, metallographic examination, and magnetization and electrical resistivity measurements. The lattice parameters show anisotropic x dependences, reflecting a lower symmetry of rather complex crystal structure. In the x = 0 sample, a ferromagnetic (FM) transition occurs at the Curie temperature of 255 K, which is systematically reduced with increasing x and disappears at x = 2.5 where an antiferromagnetic (AFM) ground state is realized. The Néel temperature seems to appear at x1, and grows to 143 K at x = 3 with the increment of x. In the intermediate range of x (1x2), a FM to AFM phase transition occurs below . In the AFM phase, the electrical resistivity ρ shows a Fermi surface instability characterized by the upturn of ρ below approximately . The competition between the FM and AFM states would be ascribed to the anisotropic x dependences of Fe–Fe bond lengths.
中文翻译:
以Al铁磁和反铁磁态之间竞争8.5- X的Fe 23戈12.5+ X(0≤ X ≤3)
多晶的Al 7+ X的Fe 23戈14- X型的斜方晶的Al 8.5- X的Fe 23戈12.5+ X(0≤ X通过X射线衍射测定,金相检验,和磁化强度和电阻率测量研究≤3)化合物。晶格参数显示出x各向异性,反映出相当复杂的晶体结构的对称性较低。在x = 0的样本中,居里温度发生铁磁(FM)跃迁255 K时,它随着x的增加而系统地减小,并在x = 2.5时消失,从而实现了反铁磁(AFM)基态。内尔温度似乎出现在x1,并且生长到在143ķ X = 3的增量X。在x(1X2),从FM到AFM的相变发生在下面 。在AFM阶段,电阻率ρ显示出费米表面不稳定性,其特征是ρ的上升趋势低于大约。FM和AFM状态之间的竞争将归因于Fe-Fe键长的各向异性x依赖性。