Ferromagnetic/superconducting bilayer structure: A model system for spin diffusion length estimation

We report detailed studies on ferromagnet-superconductor bilayer structures. Epitaxial bilayer structures of half metal-colossal magnetoresistive (HMCMR) La2∕3Ca1∕3MnO₃ and high-Tc superconducting (HTSC) YBa₂Cu₃O_7-δ are grown on SrTiO₃0.3em0ex(100) single-crystalline substrates using pulsed laser deposition. Magnetization $M(T)$ measurements show the coexistence of ferromagnetism and superconductivity in these structures at low temperatures. Using the HMCMR layer as an electrode for spin polarized electrons, we discuss the role of spin polarized self injection into the HTSC layer. The experimental results are in good agreement with a presented theoretical estimation, where the spin diffusion length ξFM is found to be in the range of ξFM≈100.3em0exnm.