Structural Properties of YBCO Thin Films Deposited From Different Kinds of Targets

The accommodation field of YBa₂Cu₃O_6+infin (YBCO) a thin films depends on the microstructure of the films and specifically the amount of pinning sites, which can be controlled by the type of the target used in the laser deposition. Typical values for the accommodation field at 5 K are 40-100 mT, 160 mT and 500 mT for films deposited from a micrograined, nanograined and optimally BaZrO₃ (BZO) doped targets, respectively. We present structural data on YBCO thin films prepared by laser deposition from a nanograined target, a micrograined target and nanograined targets with added BZO. The characterizations were done with XRD and TEM and it was found that the main difference in the undoped films (nano and micro) was the stiffer lattice of the nanofilms. The BZO inclusions were found to induce a large amount of dislocations to the YBCO lattice surrounding the BZO. This can explain the increase observed in the accommodation field.