$J_{c}$ Enhancement by La-Al-O Doping in Y-Ba-Cu-O Films Both in Self-Field and Under Magnetic Field

To enhance the J
_c
of YBa
₂
Cu
₃
O
_7-X
(YBCO) films both in self-field and under magnetic field, an effective strategy is to introduce artificial pinning centers and keep a good YBCO matrix at the same time. Here, we propose a new dopant: LaAlO
₃
(LAO), based on its chemical stability and small mismatch toward YBCO. A series of YBCO films with different LAO doping contents was fabricated on LAO single-crystal substrates by metal organic deposition. We observed by X-ray diffractometer measurements and scanning electron microscopy observations that although a large amount of LAO is added, YBCO still keeps a good epitaxial growth relationship with LAO. Compared with a pure YBCO film, the J
_c
value of a 5.0% LAO-doped sample is enhanced more than three times in self-field 77 K and seven times at 77 K and 1.5 T, respectively. These results indicate that LAO doping can effectively enhance the J
_c
of YBCO films both in self-field and in applied magnetic fields.