Magnetic Anisotropy Controlled by Distinct Interfacial Lattice Distortions at the La 1- x Sr x CoO 3 /La 2/3 Sr 1/3 MnO 3 Interfaces.

Interface engineering is an important approach leading to multifunctional artificial materials. Although most of the previous works focused on the effects of the rotation/tilting of interfacial oxygen octahedron on perovskite multilayers, here, we report on a new kind of lattice distortion characterized by an off-center shift of the Mn ions within the MnO6 oxygen octahedra at the interfaces of La1- x Sr x CoO3 /La2/3 Sr1/3 MnO3 /La1- x Sr x CoO3 /LaAlO3 trilayers ( x = 0-1/3), which drives the initially perpendicularly aligned magnetic axis of the La2/3 Sr1/3 MnO3 (LSMO) film toward the in-plane direction, though the film is in a strongly compressive state. It is further found that the magnetic anisotropy considerably depends on the content of Sr in La1- x Sr x CoO3 , enhancing as x decreases. The maximal anisotropy constant at 10 K is +2.5 × 106 erg/cm3 for the trilayers with x = 0, whereas it is -1.5 × 105 erg/cm3 for a bare LSMO film on LaAlO3 . On the basis of the analysis of X-ray absorption spectroscopy and the results of density functional theory calculations, we found that the off-center displacement of the Mn ions has caused a strong orbital reconstruction at interfaces, resulting in the anomalous spin orientation against magnetoelastic coupling.