Angular dependence of the critical current density in FeSe0.5Te0.5 thin films on metal substrates

Abstract

Biaxially textured FeSe0.5Te0.5 (FST) thin films were fabricated on ion-beam assisted-deposition LaMnO3 (LMO) buffered metal substrate with additional CeO2 as a buffer layer. Profiting from the implementation of CeO2 layers, the resultant FST films show a small out-of-plane misalignment of about 2.04° and an in-plane misalignment around 4.02°. In addition, the films have a high superconducting transition temperature (T c) ∼ 17 K and a comparatively high critical current density (J c) of 0.78 MA cm−2 in self-field at 4.2 K. On the other hand, a high J c peak for H//c above H//ab at temperatures below 10 K was observed, which results from grain boundaries along the c-axis. In addition, J c peaks for H//ab emerge above 10 K and become more pronounced than those for H//c at 12 K, indicating both a temperature- and field-dependent pinning mechanism. Moreover, J c(θ) data except for in the vicinity of H//ab and H//c can be successfully scaled using the anisotropic Ginzburg–Landau approach with an appropriate J c anisotropy ratio of γJ c ∼ 1.5, implying the presence of both ab-plane and c-axis correlated flux pinning centers in FST films.