High critical current density over 1MAcm(-2) at 13T in BaZrO3 incorporated Ba(Fe,Co)(2)As-2 thin film

Abstract

Achieving high critical current density (J(c)) under a high magnetic field in Fe based superconductors is indispensable for practical applications. Here we report that high critical current density over 1 MA cm(-2) in high field (13 T) can be achieved in BaZrO3 (BZO) incorporated Ba(Fe,Co) As-2(2) (Co-Ba122) thin film grown on CaF2 substrate using pulsed laser deposition. The magnetization Jc of Co-Ba122 thin film incorporated with 2 mol.% BZO reaches 1.3MA cm(-2) (H parallel to c, 13 T and 4.2 K), 14 times higher than that of pure Co-Ba122 thin film. Transmission electron microscopy observation revealed that BZO forms nanorods of similar to 4 nm in average diameter with mean separation of 10-11 nm which corresponds to a matching field of about 17-20 T. Incorporating BZO in Co-Ba122 thin films led to a strong vortex pinning effect and a significant enhancement of J(c) because a high density of BZO nanorods could form in the superconducting matrix without significant degradation of T-c, and the diameter of BZO nanorods is approximately twice the coherence length of Co-Ba122 (xi(ab)(0) similar to 2.5 nm) which is the optimal size as pinning centers.