Lower symmetrical behaviour of electronic state in the FeAs plane of Ba(Fe1-xCox)2As2 -75As NMR study-

27th International Conference on Low Temperature Physics

Toyoda, Masayuki^1 ; Kobayashi, Yoshiaki^1 ; Itoh, Masayuki^1 ; Sato, Masatoshi^2

Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya

464-8602, Japan^1

Research Center for Neutron Science and Technology, Comprehensive Research Organization for Science and Society (CORSS), 162-1 Shirakata, Tokai

319-1106, Japan^2

关键词: Electric field gradients;    Fe sites;    In-plane anisotropy;    NMR measurements;    NMR spectrum;    NMR studies;    Tetragonal phase;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/2/022029/pdf
DOI  :  10.1088/1742-6596/568/2/022029

来源: IOP

【 摘 要 】

To investigate The anisotropy within The FeAs plane in The tetragonal phase of Ba(Fe1-xCox)2As2,75As NMR measurements on The electric field gradient (EFG) at The As site have been carried out for a Ba(Fe1-xCox)2As2single crystal of x∼0.08 with The superconducting (SC) transition temperature of Tc∼23 K. We present a method how to analyse The75As NMR spectra and deduce The anisotropic parameter of The EFG, η, that shows The electric inplane anisotropy at The As site. The EFG of The As site with no Co atoms at The nearest and next nearest Fe sites has The η value of 0.08-0.10 similar to that in The non-SC samples of x∼0.02 in The tetragonal phase. The in-plane anisotropy in The x∼0.08 sample remains even near Tc. We discuss The relationship between The in-plane anisotropy and local physical properties.