Matching field effects in c-axis in-plane aligned a-axis-oriented YBa2Cu3Oy films with two-dimensional artificial pinning centers induced by multilayered nano-structures

摘要

A relationship between microstructures of YBa2Cu3Oy (Y123) films with two-dimensional artificial pinning centers (2D APCs) and their critical current density (Jc), especially under matching fields (Bφ), is discussed. Using a pulsed laser deposition (PLD) method, c-axis in-plane aligned a-axis-oriented Y123/Pr123 multilayer films were grown on substrates. The Pr123 interlayer distance was changed by controlling a target shape and its rotation speed in the PLD process. The multilayer structure was observed in cross-sectional transmission electron microscopy images. Critical temperatures of the films decrease as the Y123 layer becomes thinner. The magnetic field (B) dependence of Jc showed that the interlayers act as 2D APCs in multilayer films. The matching effects were observed in two ways: Jc(B-c)/Jc(B -a)–B curves and irreversibility lines.