Sefrioui, ZouhairCros, V.Barthélémy, A.Peña, V.León Yebra, CarlosSantamaría Sánchez-Barriga, JacoboVarela Del Arco, MaríaPennycook, S.J.2023-06-202023-06-202006-06-090003-695110.1063/1.2162674https://hdl.handle.net/20.500.14352/51419© 2006 American Institute of Physics. One of the authors Z.S. gratefully acknowledges financial support from Flores Valles. Work supported by MCYT MAT 2002-2642, CAM GR-MAT-0771/2004, UCM PR3/04- 12399, and Fundación Ramón Areces. This research was partially sponsored by the Laboratory Directed Research and Development Program of ORNL, managed by UT-Batelle, LLC, for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The authors thank M. Bibes for fruitful discussion.We report large tunneling magnetoresistance in La_(0.7)Ca_(0.3)MnO_(3) (8 nm)/PrBa_(2)Cu_(3)O_(7) (2.4 nm)/La_(0.7)Ca_(0.3)MnO_(3) (50 nm) junctions. The coherent growth of the cuprate on the manganite allows the deposition of ultrathin barriers which are continuous and flat over long lateral distances. Epitaxial strain causes the top layer to be a weaker ferromagnet without a significant decrease in the spin polarization.engjournal articlehttp://dx.doi.org/10.1063/1.2162674http://scitation.aip.org/open access537Spin polarizationJunctionsFilms.ElectricidadElectrónica (Física)2202.03 Electricidad