Enhancement of critical current densities by the longitudinal magnetic field effect in multilayered SmBa₂Cu₃O_<i>y</i>films controlling the film thickness

Abstract

We report on the film thickness and the interface density dependence of critical current density (J c) in multilayered SmBa2Cu3O y (SmBCO) films with short BaHfO3 (BHO) nanorods under the force-free state. In the investigation into the film thickness dependence of J c, we fixed the layer thickness and changed the total film thickness. However, in the investigation into the interface density dependence of J c, we fixed the total film thickness and changed each layer's thickness. We observed the J c peaks via the longitudinal magnetic field effect on multilayered films which have a certain film thickness of over 400 nm and a certain interface density of over 80 layers/μm. We considered that two types of flux pinning were needed for the J c enhancement and these were against the force-free torque in the ab plane and the Lorentz force along the c-axis.