Low thermal expansion behavior and transport properties of Ni and Ge co-doped manganese nitride materials at cryogenic temperatures

详细信息    查看全文

• 作者：Rongjin Huang ; Xinxin Chu ; Zhixiong Wu ; Laifeng Li and Xiangdong Xu
• 刊名：Applied Physics A: Materials Science & Processing
• 出版年：2010
• 出版时间：May, 2010
• 年：2010
• 卷：99
• 期：2
• 页码：465-469
• 全文大小：567.1 KB

文摘

A series of Ni and Ge co-doped manganese nitride materials were fabricated by mechanical ball milling followed by solid-state sintering. Their thermal expansion properties and electrical and thermal conductivities were investigated in the temperature range of 77–300 K. The results show that Ni and Ge co-doped manganese nitride materials have negative thermal expansion (NTE), and the operation-temperature window of NTE shifts toward the lower temperature region and the variation of linear thermal expansion (ΔL/L _(300K)) in the operation-temperature window of NTE decreases with increasing Ni content. The combination of these two factors results in a low coefficient of thermal expansion (CTE) at cryogenic temperatures. The average CTE of Mn₃(Cu_0.2Ni_0.4Ge_0.4)N drops to ‘zero’ in the temperature range of 190–77 K. The values of electrical and thermal conductivities of the Ni and Ge co-doped manganese nitride materials are in the ranges of 2–3¡Á103 (ohm cm)−1 and 1.6–3.4 W (m K)−1, respectively.