Improved Pinning in YBCO Based Quasi-Multilayers Prepared by On- and Off-Axis Pulsed Laser Deposition

At higher magnetic fields, the critical current density in coated conductors based on biaxially textured metal substrates is limited by the intragrain pinning properties. Therefore, artificial pinning centers were introduced in Y123 films using on-axis as well as off-axis pulsed laser deposition. The nanosized particles were prepared using a quasi-multilayer approach where Hf metal layers having a thickness less than one unit cell were incorporated into Y123 films. Due to the oxidizing deposition atmosphere and solid state reaction with the Y123 phase, nanometer sized perovskite precipitates, which are biaxially textured with a well-defined relationship towards the Y123 lattice were formed. The pinning properties and the anisotropy were characterized using magneto-transport measurements at various fields and temperatures. A significant improvement of as well as irreversibility field B irr could be observed in the off-axis deposited quasi-multilayers.