Flux Pinning Properties in YBCO Thin Films With Self-Aligned Magnetic Nanoparticles

In this work, we conducted a systematic investigation on both self-field and in-field performance of YBa₂Cu₃O_7-δ (YBCO) thin films with self-aligned (ordered) Fe₂O₃ magnetic nanoparticles and compared with a pure YBCO reference sample. The doping architectures include YBCO films with ordered Fe₂O₃ nanoparticles on the top, Fe₂O₃:CeO₂ nanocomposite on the top, with self-aligned Fe₂O₃ nanoparticles at the bottom and with multilayered nanoparticles in the matrix. All samples were prepared by pulse laser deposition (PLD). We explored the self-field and in-field performance (Jcsf and Jcin-field(H//c)) of the YBCO films with the vibrating sample magnetometer (VSM) in a physical property measurement system (PPMS) at various temperatures and correlated with their microstructural characteristics. This work suggests that the self-aligned Fe₂O₃ nanoparticles can form in YBCO matrix without severe deterioration of YBCO superconducting properties. Instead, they work as effective pinning centers at all temperatures measured and the multilayer sample and the sample with Fe₂O₃ : CeO₂ nanocomposite show the best pinning properties among all the samples examined.