The low temperature magnetostructural transition in Pr0.50Sr0.50CoO3: Bulk versus thin film behavior
Abstract
Under the terms of the license Creative Commons Attribution 3.0 Unported License to their work. ; We present a comparative study of the magnetic transitions in metallic Pr0.50Sr0.50CoO3 (PSCO) perovskites prepared in polycrystalline and thin film forms. As the bulk system, the strained epitaxial PSCO (010) film grown on LAO (100) is metallic in all the temperature range, with a ferromagnetic transition at 225 K, close to Tc ∼ 235 K in the ceramic PSCO specimen. Unlike the bulk system, the PSCO film does not show the second magnetic transition on cooling. In the ceramic sample, the second magnetic transition is coupled to an orthorhombic-to-monoclinic symmetry change. There is a contraction of the average ⟨Pr-O⟩ bond distance in the monoclinic phase below Ta, but the ⟨Co-O⟩ bond length is not modified across the transition. The orthorhombic to monoclinic structural transition stabilizes four short Pr-O2 bonds to basal oxygens in CoO6 octahedra. A strong hybridization of Pr 4f and O 2p orbitals in these bonds can be activated at Ta and probably assist the magnetostructural transition. ; We thank financial support from MICINN (Spanish government) under Projects MAT2009-09308, MAT2012-38213-C02-02, and CSD2007-00041 (NANOSELECT), and the ILL for granting beamtime. J.P-P thanks CSIC for JAE-Pre contract. ; Peer reviewed
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