Dimensionality engineering dependence of vertical magnetization shift and magnetic anisotropy evolution in manganite superlattices

Abstract

The manganite superlattices consisting of a ferromagnetic La0.7Sr0.3MnO3 (LSMO) metal and a G-type antiferromagnetic SrMnO3 (SMO) insulator have been investigated in this work. Two very intriguing effects have been observed in these LSMO/SMO superlattices. The first one is the coexistence of the robust exchange bias and the evident vertical magnetization shift in the thicker superlattices. The second is the magnetic anisotropy variation from planar to perpendicular with increasing SMO layer thickness. These two novel phenomena have been confirmed by the electric transport anisotropy measurements and the microscopic magnetic domain switching images. Moreover, the X-ray linear dichroism experiments and first-principle calculations have revealed the orbital reconstruction dependence on the SMO layer thickness. It is noteworthy that the vertical magnetization shift and perpendicular magnetic anisotropy are usually observed in intrinsic out-of-plane magnetic easy axis materials such as SrRuO3-based heterostructures. However, the spins within LSMO films preferably orient towards the in-plane direction. Therefore, a new microscopic method for vertical magnetization shift and magnetic anisotropy manipulation has been developed, enabling the discovery of emergent phenomena as well as the control of the magnetic properties.