ACTA

Superconductivity and Ferromagnetism in La_0.67Sr_0.33MnO₃/YBa₂Cu₃O₇ Nanosized Heterostructures

H. Lochmajer^a,b, M. Matusiak^a,b, G. Urbanik^b,c, P. Przyslupski^d and K. Rogacki^a,b,c
^aInstitute of Low Temperature and Structure Research, PAS, Okólna 2, 50-422 Wrocław, Poland
^bCentre for Advanced Materials and Smart Structures, PAS, Okólna 2, 50-422 Wrocław, Poland
^cInternational Laboratory of High Magnetic Fields and Low Temperatures, PAS, Gajowicka 95, 53-421 Wrocław, Poland
^dInstitute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland

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In this work we present recent experimental studies of heterostructures composed of ferromagnetic La_0.67Sr_0.33MnO₃ (LSMO) and superconducting YBa₂Cu₃O₇ (YBCO) multilayers grown by dc sputtering method. The transport and magnetic properties of the large set of heterostructures were investigated in a wide temperature range from 2 to 400 K and in fields up to 12.5 T. The resistivity and the upper critical field were measured for samples with the plane active dimensions 1.5× 5 mm². The Nernst effect was studied in the mixed state revealing the characteristic temperature dependence of the Nernst signal which was correlated with variation of the upper critical field. We have observed an influence of the magnetic LSMO layer on the superconducting properties of the adjacent YBCO layer which consists in a substantial reduction of the superconducting critical temperature and a small lowering of the upper critical field.

DOI: 10.12693/APhysPolA.130.588
PACS numbers: 74.25.fc, 74.25.fg, 74.78.Fk