Unusually high critical current of clean P-doped BaFe2As2 single crystalline thin film

Abstract

Microstructura lly clean, isov alently P-doped BaFe2As2 (Ba-122) single crystalline thin films have been prepared on MgO (001) substrates by molecular beam epitaxy. These films show a superconducting transition temperature (Tc) of over 30 K although P content is around 0.22, which is lower than the optimal one for single crystals (i.e., 0.33). The enhanced Tc at this doping level is attributed to the in-plane tensile strain. The strained film shows high transport self-field critical current densities (Jc) of over 6 MA/cm2 at 4.2 K, which are among the highest for Fe based superconductors (FeSCs). In-field Jc exceeds 0.1 MA/cm2 at m0H = 35 T for H||ab and m0H = 18 T for H||c at 4.2 K, respectively, in spite of moderate upper critical fields compared to other FeSCs with similar Tc. Structural investigations reveal no defects or misoriented grains pointing to strong pinning centers. We relate this unexpected high Jc to a strong enhancement of the vortex core energy at optimal Tc, driven by in-plane strain and doping. These unusually high Jc make P-doped Ba-122 very favorable for high-field magnet applications.

5 pages, 4 figures

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Cited by in corpus (5)

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• High-field transport properties of a P-doped BaFe2As2 film on technical substrate
• Superconducting properties of Ba(Fe1-xNix)2As2 thin films in high magnetic fields
• Giant enhancement of critical current density at high field in superconducting (Li,Fe)OHFeSe films by Mn doping
• Study of the second magnetization peak and the pinning behaviour in Ba(Fe${}_{0.935}$Co${}_{0.065}$)${}_2$As$_2