Enhancement of the superconducting transition temperature by an external magnetic field parallel to the plane of La0.7Sr0.3MnO3/YBa2Cu3O7/La0.7Sr0.3MnO3 trilayersK. Dybko, K. Werner-Malento, M. Sawicki and P. Przyslupski
Institute of Physics, Polish Academy of Sciences - Al. Lotników 32/46, 02-668 Warsaw, Poland, EU
received 24 November 2008; accepted in final form 15 February 2009; published March 2009
published online 20 March 2009
We investigate the superconducting transition temperature of epitaxial La0.7Sr0.3MnO3/YBa2Cu3O7/La0.7Sr0.3MnO3 (LSMO/YBCO/LSMO) trilayers as a function of the magnetic field parallel to the layer structure. In these structures, the magnetic moment of the half-metallic ferromagnet LSMO is parallel to the plane of the film. The coercivity- and saturation field of the top and bottom LSMO layer could be independently tuned by adjusting their thickness. The application of a magnetic field increased the superconducting transition temperature by about 1.6 K with respect to the demagnetized state of the LSMO. Three possible mechanisms of the enhancement are considered. These are the stray fields due to domain walls, spin polarization of the current, and the formation of an odd triplet superconducting state.
74.78.Fk - Multilayers, superlattices, heterostructures.
74.62.-c - Transition temperature variations.
85.75.-d - Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields.
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