Structural and transport properties of Sr_2VO_(3-δ)FeAs superconductors with different oxygen deficiencies  

作　　者：HAN Fei ZHU XiYu MU Gang CHENG Peng SHEN Bing ZENG Bin WEN HaiHu 

机构地区：[1]National Laboratory for Superconductivity,Institute of Physics and Beijing National Laboratory for Condensed Matter Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2010年第7期1202-1206,共5页中国科学:物理学、力学、天文学(英文版)

基　　金：supported by the National Natural Science Foundation of China,the National Basic Research Program of China (Grant Nos. 2006CB601000 and 2006CB921802);the Chinese Academy of Sciences Project (Grant No. ITSNEM)

摘　　要：Sr2VO3-δFeAs superconductors with different oxygen deficiencies have been successfully fabricated.It is found that the superconducting transition temperature drops down monotonically with the increase of nominal oxygen deficiency.The diminishing of superconductivity is accompanied by the enhancement of residual resistivity,indicating an anomalous scattering effect induced by the oxygen deficiency.The highest superconducting transition temperature at about 36 K is achieved near the stoichiometrical sample Sr2VO2.9FeAs.The Hall effect measurements reveal that the density of charge carriers(electron-like here) varies qualitatively with the increase of nominal oxygen deficiency.Magnetotransport measurements show that the superconducting transition changes from one-step-like shape at low fields to two-step-like one at high fields,indicating an enhanced vortex motion due to the high anisotropy.Sr2VO3-δFeAs superconductors with different oxygen deficiencies have been successfully fabricated.It is found that the superconducting transition temperature drops down monotonically with the increase of nominal oxygen deficiency.The diminishing of superconductivity is accompanied by the enhancement of residual resistivity,indicating an anomalous scattering effect induced by the oxygen deficiency.The highest superconducting transition temperature at about 36 K is achieved near the stoichiometrical sample Sr2VO2.9FeAs.The Hall effect measurements reveal that the density of charge carriers(electron-like here) varies qualitatively with the increase of nominal oxygen deficiency.Magnetotransport measurements show that the superconducting transition changes from one-step-like shape at low fields to two-step-like one at high fields,indicating an enhanced vortex motion due to the high anisotropy.

关 键 词：iron-based superconductor oxygen deficiency transport properties high anisotropy 

分 类 号：O511[理学—低温物理]