Magnetically Defined Birr and Bc2 in BaCeO3 Doped YBa2Cu3O6+x Thin Films Grown Under Tensile and Compressive Strain
: H. Huhtinen, H. Palonen, M. Malmivirta, R. Jha, V.P.S. Awana, P. Paturi
Publisher: IEEE
: 2015
: IEEE Transactions on Applied Superconductivity
: IEEE Trans Appl Supercond
: 6605405
: 25
: 3
: 5
: 1051-8223
DOI: https://doi.org/10.1109/TASC.2014.2374792(external)
The effect of lattice mismatch between the film and the substrate on magnetically obtained irreversibility field Birr and upper critical field Bc2 is investigated in BaCeO3 (BCO)-doped YBa2Cu3O6+x (YBCO) thin films prepared by pulsed laser deposition on SrTiO3 (STO), SrLaAlO4 (SLAO), MgO, and (67%)Pb(Mg1/3Nb2/3)O3-(33%)PbTiO3 (PMN-PT) substrates. BCO has been observed to form epitaxially grown, nonelongated, and randomly distributed particles within the whole concentration range of 0-10 wt.%. Therefore, the optimal concentration of 4 wt.% BCO is selected, where the highest Jc in the high applied magnetic field range can be observed. The observed flux pinning performance is connected to the structural properties of the films, where substrate-induced uniform strain; crystallographical defects such as dislocations, vacancies, and BCO-nanodot-induced microstrain; low-angle grain boundaries; and YBCO lattice ordering, in general, have substantially different roles at different crystallographical directions.