Enhancement of the thermoelectric performance of half-metallic full-Heusler Mn_(2)VAl alloys via antisite defect engineering and Si partial substitution  

作　　者：Hezhang Li Kei Hayashi Zhicheng Huang Hiroto Takeuchi Gakuto Kanno Jing-Feng Li Yuzuru Miyazaki 

机构地区：[1]Department of Precision Instrument,Tsinghua University,Beijing,100084,China [2]Department of Applied Physics,Graduate School of Engineering,Tohoku University,Sendai,980-8579,Japan [3]State Key Laboratory of New Ceramics and Fine Processing,School of Materials Science and Engineering,Tsinghua University,Beijing,100084,China

出　　处：《Journal of Materiomics》2024年第2期511-519,共9页无机材料学学报（英文）

基　　金：supported by Grant-in-Aid for JSPS Fellows(no.20J11073)from the Japan Society for the Promotion of Science and by the Tsinghua-Tohoku Collaborative Research Fund from Tsinghua University and Tohoku University;supported by the Grant-in-Aid for Scientific Research(B)(nos.20H01841,22H02161)from the Japan Society for the Promotion of Science.

摘　　要：A half-metallic full-Heusler Mn_(2)VAl alloy is a potential p-type thermoelectric material that can directly generate electricity from waste heat via the Seebeck effect.For practical use,the Seebeck coefficient S of Mn_(2)VAl should be increased while maintaining a high electrical conductivity s from its half-metallic character.Herein,we achieved this objective through antisite defect engineering.Theoretically,it was predicted that the S was maximized by regulating partial density of states of majority-spin sp-electrons through the control of the fraction of antisite defect,f_(AD),between V and Al atoms in Mn_(2)VAl.Experi-mentally,a significant increase in S and a slight decrease in s were observed for an Mn_(2)VAl sample with an optimal fAD=33%,enhancing the thermoelectric power factor PF by 2.7 times from an Mn_(2)VAl sample with fAD=14%.Furthermore,we combined the antisite defect engineering with a partial substitution method.An Mn_(2)V(Al_(0.96)Si_(0.04))sample with fAD=33%exhibited the highest PF=4.5×10^(-4)W·m^(-1)·K^(-2)at 767 K among the samples.The maximum dimensionless figure-of-merit zT of the Mn_(2)V(Al_(0.96)Si_(0.04))sample with f_(AD)=33%was measured to be 3.4×10^(-2)at 767 K,which is the highest among the p-type half-metallic full-Heusler alloys.

关 键 词：Half metal Full-Heusler alloy Thermoelectric properties Antisite defect Partial substitution 

分 类 号：TG14[一般工业技术—材料科学与工程]