Origin of the uniaxial magnetic anisotropy in La0.7Sr0.3MnO3 on stripe-domain BiFeO3

The La0.7Sr0.3MnO3/BiFeO3 (LSMO/BFO) heterostructure has been a model system to study the interaction between ferroic order parameters at a complex oxide interface. In this study, uniaxial magnetic anisotropy is artificially induced in LSMO thin film grown on BFO with electrically patterned stripe domains. Variable-field magnetic force microscopy is exploited to investigate the in situ magnetic switching dynamics and subsequently determine the magnetic easy axis of the LSMO thin film. Intriguingly, one-to-one correspondence between the magnetization of LSMO and the polarization of BFO is found. The observed uniaxial magnetic anisotropy is attributed to the magnetocrystalline anisotropy of the LSMO, which is induced by the shear strain of the BFO lattice, rather than the interfacial magnetic coupling which would be more naturally assumed. This finding highlights the crucial role of lattice coupling at a complex oxide interface. When multiple-order parameters come into play at the heterointerface, special care is needed to deconvolute their effects on the related physical properties.