反钙钛矿结构化合物Ga1-xN0.8Mn3+x(0<x≤0.3)的制备及负热膨胀研究-中国材料进展

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Title:: Preparation and negative thermal expansion in anti-perovskite Ga1-xN0.8Mn3+x(0<x≤0.3)

作者:: 郭新格1; 2; 林建超1; 童鹏1; 孙玉平1; 2; 3; 1.材料物理重点实验室，固体物理所，中国科学院合肥物质科学研究院，安徽合肥

2.中国科学技术大学，安徽合肥

3.强磁场科学中心，中国科学院，安徽合肥

Author(s):: Guo Xinge1; 2; Lin Jianchao1; Tong Peng1; Sun Yuping1; 3; 2; 1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Anhui Hefei
2. University of Science and Technology of China, Anhui Hefei
3. High Magnetic Field Laboratory, Chinese Academy of Sciences, Anhui Hefei

摘要:: 反钙钛矿结构锰氮化物的负热膨胀效应近年来获得了广泛关注。我们利用固相反应法制备出系列反钙钛矿结构化合物
Ga1-xN0.8Mn3+x(0<x≤0.3)，并对其热膨胀性能及电输运性质展开研究。结果发现，随着Mn原子对Ga原子替换量（x）的增加，Ga1-xN0.8Mn3+x中磁体积效应的温区被展宽且向低温区移动，呈现负热膨胀行为。其中，x=0.2和0.25样品的负膨胀效应的温度范围分别是292K-339K和256K-309K，对应线膨胀系数分别为-48ppm/K和-42ppm/K。与之相对应，电阻率也在对应温区出现反常行为。我们认为Mn替代Ga对（111）面内Г5g反铁磁序的扰动可能是导致MVE效应展宽为NTE效应的主要因素。

Abstract:: Antiperovskite manganese nitrides have attracted much attention recently because of the negative thermal expansion (NTE) they display. A new series of anti-perovskite manganese nitrides Ga1-xN0.8Mn3+x(0<x≤3) were prepared using solid–state reaction method. In the present work, the negative thermal expansion (NTE) and the electrical transport were studied. With the increment of Mn-doping level, the temperature span of the magnetovolume effect not only broadens but also shifts toward lower temperatures. The temperature span of NTE is 292-339K and 256-309K, and the corresponding coefficient of linear thermal expansion is -48ppm/K and -42ppm/K, respectively. An abnormal behavior of resistivity was observed, in line with the contraction of the lattice. The NTE behaviors may be attributed to the disturbance of the Γ5g antiferromagnetic ground state by partially substituting the Ga atoms with Mn.