文章信息/Info

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; 童鵬1; 孫玉平1; 2; 3

1.材料物理重點實驗室，固體物理所，中國科學院合肥物質科學研究院，安徽 合肥

2.中國科學技術大學，安徽 合肥

3.強磁場科學中心，中國科學院，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

關鍵詞:

負熱膨脹; 反鈣鈦礦結構; 反鐵磁序

DOI:

10.7502/j.issn.1674-3962.2015.07.06

文獻標志碼:

A

摘要:

反鈣鈦礦結構錳氮化物的負熱膨脹效應近年來獲得了廣泛關注。我們利用固相反應法制備出系列反鈣鈦礦結構化合物

Ga1-xN0.8Mn3+x(0<x≤0.3)，并對其熱膨脹性能及電輸運性質展開研究。結果發現，隨著Mn原子對Ga原子替換量（x）的增加，Ga1-xN0.8Mn3+x中磁體積效應的溫區被展寬且向低溫區移動，呈現負熱膨脹行為。其中，x=0.2和0.25樣品的負膨脹效應的溫度范圍分別是292K-339K和256K-309K，對應線膨脹系數分別為-48ppm/K和-42ppm/K。與之相對應，電阻率也在對應溫區出現反常行為。我們認為Mn替代Ga對（111）面內Г5g反鐵磁序的擾動可能是導致MVE效應展寬為NTE效應的主要因素。

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.