中国物理B ›› 2016, Vol. 25 ›› Issue (6): 67402-067402.doi: 10.1088/1674-1056/25/6/067402

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Structural stabilities and electrical properties of Ba8Ga16-xCuxSn30 single crystals under high temperatures

Jin-Song Wang(王劲松), Feng Cheng(程峰), Hong-Xia Liu(刘红霞), De-Cong Li(李德聪), Lan-Xian Shen(申兰先), Shu-Kang Deng(邓书康)   

  1. 1 Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500, China;
    2 Photoelectric Engineering College, Yunnan Open University, Kunming 650500, China
  • 收稿日期:2015-12-25 修回日期:2016-02-23 出版日期:2016-06-05 发布日期:2016-06-05
  • 通讯作者: Shu-Kang Deng E-mail:skdeng@126.com
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant No. 51262032).

Structural stabilities and electrical properties of Ba8Ga16-xCuxSn30 single crystals under high temperatures

Jin-Song Wang(王劲松)1, Feng Cheng(程峰)1, Hong-Xia Liu(刘红霞)1, De-Cong Li(李德聪)2, Lan-Xian Shen(申兰先)1, Shu-Kang Deng(邓书康)1   

  1. 1 Education Ministry Key Laboratory of Renewable Energy Advanced Materials and Manufacturing Technology, Yunnan Normal University, Kunming 650500, China;
    2 Photoelectric Engineering College, Yunnan Open University, Kunming 650500, China
  • Received:2015-12-25 Revised:2016-02-23 Online:2016-06-05 Published:2016-06-05
  • Contact: Shu-Kang Deng E-mail:skdeng@126.com
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant No. 51262032).

摘要:

Single crystalline samples of type-I and type-VIII Ba8Ga16-xCuxSn30 (x = 0, 1) clathrates are prepared by the Sn-flux method. Effects of Cu-doping on stability and electrical properties of Ba8Ga16Sn30 single crystal are explored by first-principle and experiment. All samples are heated to different high temperatures and maintained at these temperatures for 120 min and then cooled to room temperature to explore their structural stabilities. Results from DTA and powder x-ray diffraction analysis indicate that type-I Ba8Ga16Sn30 structure is transformed into type-VIII phase after the sample has been heated to 185℃. Type-VIII BGS is stable during heating and cooling, but type-VIII Ba8Ga15CuSn30 decomposes into Sn and Ba(Ga/Sn)4 during cooling. Meanwhile, the electrical properties of type-I samples are measured, their electrical conductivities are enhanced, and the Seebeck efficient is reduced with Cu substitution. The type-I samples after phase transformations show the electrical characteristics of type-VIII samples.

关键词: thermoelectric materials, clathrate, n-type conduction

Abstract:

Single crystalline samples of type-I and type-VIII Ba8Ga16-xCuxSn30 (x = 0, 1) clathrates are prepared by the Sn-flux method. Effects of Cu-doping on stability and electrical properties of Ba8Ga16Sn30 single crystal are explored by first-principle and experiment. All samples are heated to different high temperatures and maintained at these temperatures for 120 min and then cooled to room temperature to explore their structural stabilities. Results from DTA and powder x-ray diffraction analysis indicate that type-I Ba8Ga16Sn30 structure is transformed into type-VIII phase after the sample has been heated to 185℃. Type-VIII BGS is stable during heating and cooling, but type-VIII Ba8Ga15CuSn30 decomposes into Sn and Ba(Ga/Sn)4 during cooling. Meanwhile, the electrical properties of type-I samples are measured, their electrical conductivities are enhanced, and the Seebeck efficient is reduced with Cu substitution. The type-I samples after phase transformations show the electrical characteristics of type-VIII samples.

Key words: thermoelectric materials, clathrate, n-type conduction

中图分类号:  (Thermoelectric effects)

  • 74.25.fg
74.25.fc (Electric and thermal conductivity) 81.10.-h (Methods of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation)