Exchange bias induced by surface inhomogeneities in epitaxial Pr0.7Sr0.3MnO3/ La0.5Ca0.5MnO3 bilayer film

The epitaxial growth of bilayer film made of ferromagnetic metal material Pr_0.7Sr_0.3MnO₃ and charge-ordering insulating material La_0.5Ca_0.5MnO₃ on single crystalline SrTiO₃ (001) substrate. High resolution X-ray diffraction and atomic force microscopy analyses show the single crystalline nature of the film. Further atomic force microscopy measurement shows the presence of non-stoichiometric large particulates at the film surface, imparting an overall inhomogeneous composition to the film. This implied that the variation of crystalline structure occurred due to inhomogeneous composition. Magnetic measurement results indicate that the inhomogeneous composition could cause inhomogeneity of magnetic phase which in turn reduce ferromagnetism and enhance exchange bias effect.