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 YBa
₂
Cu
₃
O
_7-δ
(YBCO) thin films with self-aligned (ordered) Fe
₂
O
₃
magnetic nanoparticles and compared with a pure YBCO reference sample. The doping architectures include YBCO films with ordered Fe
₂
O
₃
nanoparticles on the top, Fe
₂
O
₃
:CeO
₂
nanocomposite on the top, with self-aligned Fe
₂
O
₃
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 Fe
₂
O
₃
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 Fe
₂
O
₃
: CeO
₂
nanocomposite show the best pinning properties among all the samples examined.