Magneto-Optics of Spontaneous and Field Induced Vortices in Twinned YBa2Cu3O7-δ/La1-xSrxMnO3 Bilayers
R. Gerbaldo, G. Ghigo, L. Gozzelino, F. Laviano, E. Mezzetti, B. Minetti
Department of Physics, Politecnico di Torino, c.so Duca degli Abruzzi 24, 10128 Torino, Italy and INFN Sez. Torino, Via P. Giuria 1, 10125 Torino, Italy
P. Przysłupski, A. Tsarou and A. Wiśniewski
Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland
Full Text PDF
Received: 04 09 2006;
The electromagnetic coupling between the magnetic and the superconducting layers in perovskite heterostructures is investigated by means of the magneto-optical technique. The quantitative imaging of the magnetic field distribution allows the high-resolution reconstruction of local supercurrent density. Two phenomena arising from the coupling between manganite layer and the YBa2Cu3O7-δ superconducting film deposited on top are addressed, i.e., the local effects of the electronic coupling between the compounds and the interaction between the manganite magnetic moments and the vortices in the superconductor. The first issue can be quantified in terms of the local superfluid density depression/enhancement in correspondence to the underlying magnetic structure, both domains and domain walls (in dependence on the orientation and sign of the local magnetization) and of the spontaneous, macroscopic screening current loops generated by the manganite domain walls. The interaction between the local manganite magnetization and the superconducting vortices is also influenced by structural defects because they modulate the magnetic pattern of the manganite. Different channelling phenomena in correspondence to the natural twin boundaries of the substrate, but locally magnetized by pinned domain walls of the manganite on their locations, are recognized.
DOI: 10.12693/APhysPolA.111.47
PACS numbers: 74.25.Ha, 74.25.Qt, 74.78.Db, 74.78.Fk