Comparison of the structural and magnetic properties of the two ternary silicides Nd₆Ni_1.67Si₃ and Nd₆Co_1.67Si₃

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• 作者：E. Gaudin ; S. Tencé ; B. Chevalier
• 关键词：Nd₆Co_1.67Si₃ ; Nd₆Ni_1.67Si₃ ; Intermetallic compounds ; Magnetic properties ; Rare-earth compounds ; Crystal structure ; Disordered structure
• 刊名：Solid State Sciences
• 出版年：2008
• 期刊代码：98_12932558
• 类别：ch
• 出版时间：April 2008
• 卷：10
• 期：4
• 页码：481-485
• 文件大小：376 K

摘要

Single phases of Nd₆Ni_1.67Si₃ and Nd₆Co_1.67Si₃ were prepared by arc melting of a stoichiometric mixture of the elements followed by annealing at 1073 K. The structure of Nd₆Co_1.67Si₃ was determined from single-crystal X-ray data with the space group P6₃/m and the lattice parameters a = 11.950(4) Å and c = 4.232(2) Å. Its structure derives from the structure of the aristotype compound Ce₆Ni_1.67Si₃. A strong disorder of cobalt atoms in the chains of face-shared octahedra of neodymium is observed. Magnetization measurements reveal the existence of two ferro(ferri)magnetic transitions at 84(1) K and 38(1) K for Nd₆Ni_1.67Si₃. For Nd₆Co_1.67Si₃ it has been previously shown that also two ferro(ferri)magnetic transitions occur at 84 K and 35 K. The comparison between the magnetic properties of Nd₆Ni_1.67Si₃ and Nd₆Co_1.67Si₃ shows a significant difference of the behaviour of the magnetization M versus temperature and field bc;₀H below 84 K. The curves M = f(T) obtained by field-cooled (FC) process and under bc;₀H = 0.1 T show an increase of M below 35 K for Nd₆Co_1.67Si₃ and on the contrary, a decrease of M below 38 K for Nd₆Ni_1.67Si₃. This difference suggests the occurrence at low temperature of different magnetic structures for these two ternary silicides.