Critical current density anisotropy and scaling of Ag/(Ba,K) Fe2As2 tapes
羅 珺怡, 岡田 達典, 淡路 智, 鈴木 匠 （東北大）； 黄 河, 张 现平, 马 衍伟 （IEECAS）
Abstract:In order to understand the Jc anisotropy and pinning mechanisms of Ag-sheath flat-rolled (Ba,K)Fe2As2 (Ba122) tapes (Tc ~ 38 K), the magnetic field and angular dependences of Jc of the tapes were measured at 4.2 K and high-temperatures over 30 K. Anomalous Jc anisotropy that Jc for B∥c became larger than those for B∥ab was observed in low field below the crossover field Bco. Based on the effective-mass model, the angular dependence of Jc is well scaled in high field above Bco, which means that the Jc anisotropy is dominated by effective-mass anisotropy and the pinning mechanism is isotropic. However, Jc can’t be scaled below Bco, which indicates an additional pinning mechanism. It is considered to be explained by the additional pinning due to nanoparticles.