Perpendicular magnetic anisotropy induced by La _2/3 Sr _1/3 MnO ₃ –YBaCo ₂ O _{5+ δ} interlayer coupling

Abstract

Abstract Heterostructure with a symmetry-mismatched interface provides a promising playground for the exploration of emergent phenomena. Herein, we report a systematic investigation on La 2/3 Sr 1/3 MnO 3 /YBaCo 2 O 5+ δ (LSMO/YBCO) grown on SrTiO 3 , a heterostructure formed by perovskite oxides of different symmetry. A high-resolution lattice image shows the formation of high-quality perovskite LSMO and A-site cation-ordered oxygen-deficient double perovskite YBCO, without any signatures of atomic reconfiguration at the interface. Surprisingly, the YBCO-buffered LSMO exhibits perpendicular magnetic anisotropy (PMA), though bare LSMO film is in-plane anisotropic. The PMA is robust, appearing even when the thickness of YBCO is only one unit cell. The typical anisotropy constant is ∼4 × 10 6 erg cm −3 . X-ray absorption spectroscopy analysis reveals a preferential occupation of the d 3 z 2 − r 2 orbital compared with d x 2 − y 2 , which is confirmed by density functional theory calculations. This orbital reconstruction accounts for the PMA. The formation of a covalent bond between Mn and Co caged by different oxygen polyhedrons, an octahedron and a square pyramid, respectively, stabilizes the orbital reconstruction, resulting in anomalous spin orientation.