论文部分内容阅读
Single crystalline samples of type-I and type-VIII Ba_8Ga_(16-x)Cu_xSn_(30)(x = 0,1) clathrates are prepared by the Snflux 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 xray diffraction analysis indicate that type-I Ba_8Ga_(16)Sn_(30) 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 Ba_8Ga_(15)CuSn_(30) 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.
Single crystalline samples of type-I and type-VIII Ba_8Ga_ (16-x) Cu_xSn_ (30) (x = 0,1) clathrates are prepared by the Snflux 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 capabilities. Results from DTA and powder xray diffraction analysis indicate that type-I Type-VIII BGS is stable during heating and cooling, but type-VIII Ba_8Ga_ (15) CuSn_ (30) decomposes into Sn and Ba (Ga / Sn) _4 during cooling. While the electrical properties of type-I samples were measured, their electrical conductivities are enhanced, and the Seebeck efficient is reduced with Cu substitution. type-I samples after phase transformations show the electrica l characteristics of type-VIII samples.