Negative thermal expansion and electrical properties of α-Cu2V2O7

作者：Zhang, Niu; Li, Li; Wu, Mingyi; Li, Yuxiang; Feng, Dongsheng; Liu, Cunyuan; Mao, Yanchao; Guo, Juan; Chao, Mingju^*; Liang, Erjun

来源：Journal of the European Ceramic Society, 2016, 36(11): 2761-2766.

DOI：10.1016/j.jeurceramsoc.2016.04.030

• Negative thermal expansion
• alpha-Cu2V2O7
• Solid state method
• Impedance spectrum

The orthorhombic copper(II) vanadate (alpha-Cu2V2O7) was synthesized using a solid state method, and its negative thermal expansion (NTE) and electrical properties were systematically studied. The results show that the alpha-Cu2V2O7 exhibits NTE property linearly from room temperature (RT) to 470 I( with the coefficient of thermal expansion (CTE) -5.8 x 10(-6) K-1. The coupling rotation of rigid unit modes (RUMs) caused by transverse vibrations of bridge oxygen atoms is attributed to the NTE behavior. Moreover, NTE property performs nonlinearity in 470-610 K, and the average GE is about -2.4 x 10(-6) K-1 which is caused by the synthetic action of d(9) Jahn-Teller effect of Cu2+ and small amount of micro-pores. The material exhibits low thermal expansion between 610 and 720 K with CTE 0.43 x 10(-6) K-1. The distortion effect was confirmed by UV-vis absorption spectroscopy. The impedance spectroscopy analysis shows that the alpha-Cu2V2O7 has a certain semiconductor property, which is consistent with the results of ab-initio calculation. The NTE property and pyroconductivity bring a good potential application in composite conductive ceramic and high temperature conductive materials.

• 出版日期2016-9
• 单位郑州大学; 中原工学院