Magneto-dynamic properties of complex oxide—La0.7Sr0.3MnO3/SrTiO3— heterostructure interface

Abstract

We have studied the interface magnetodynamic properties of La0.7Sr0.3MnO3/SrTiO3 (111) heterostructures by Ferromagnetic resonance spectroscopy (FMR). In addition to the bulk FMR mode, the measurements indicate a mode originating from an independently excited ferromagnetic layer at the interface. The peak-to-peak intensity of the interface mode suggests a layer thickness on the order of few unit cells. Angle resolved FMR measurements reveal a hexagonal symmetry of the magnetocrystalline anisotropy of the mode with the easy axis along the in-plane <1–10> crystallographic directions matching with the (111) surface orientation of the substrate, in contrast to bulk mode symmetry which is always found to have uniaxial symmetry caused by magnetostriction. The temperature dependence of the anisotropy and a large temperature variation in the intensity ratio of interface and bulk mode indicate a coupling of the interface to the bulk mode.