Enhanced Flux Pinning Properties in / $(J_{c})$ of $hbox{YBa}_{2}hbox{Cu}_{3}hbox{O}_{7-delta} $ (YBCO) thin films. Most of the previous work has focused on either defect pinning or magnetic pinning. In this work, we introduced a unique nanocomposite with two phases, e.g., ferrimagnetic $hbox{CoFe}_{2}hbox{O}_{4}$ and non-magnetic $hbox{CeO}_{2}$. As a demonstration, the composition of $(hbox{CoFe}_{2}hbox{O}_{4})_{0.3}(hbox{CeO}_{2})_{0.7} $ was chosen for this study. The nanocomposite was incorporated into YBCO films as multilayers, i.e., 1-, 2-, and 4-interlayers. A detailed study on the microstructural and superconducting properties was conducted. The results show that the critical temperature remains at $sim$90 K even after introducing interlayers. More importantly, the films with interlayers show enhanced self-field and in-field $J_{c}$, especially the 2-interlayer sample with $J_{c}^{sf}$ of 6.36 $hbox{MA/cm}^{2}$ at 77 K. The enhanced $J_{c}$ properties are attributed to both magnetic pinning from $hbox{CoFe}_{2}hbox{O}_{4}$ and defect pinning from $hbox{CeO}_{2}$, as well as the well-designed pinning landscapes.

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