  Manipulating magnetic anisotropy (MA) purposefully in transition metal oxides
(TMOs) enables the development of oxide-based spintronic devices with practical
applications. Here, we report a pathway to reversibly switch the lateral
magnetic easy-axis via interfacial oxygen octahedral coupling (OOC) effects in
3d-5d tricolor superlattices, i.e. [SrIrO3,mRTiO3,SrIrO3,2La0.67Sr0.33MnO3]10
(RTiO3: SrTiO3 and CaTiO3). In the heterostructures, the anisotropy energy
(MAE) is enhanced over one magnitude to ~106 erg/cm3 compared to
La0.67Sr0.33MnO3 films. Moreover, the magnetic easy-axis is reversibly
reoriented between (100)- and (110)-directions by changing the RTiO3. Using
first-principles density functional theory calculations, we find that the
SrIrO3 owns a large single-ion anisotropy due to its strong spin-orbit
interaction. This anisotropy can be reversibly controlled by the OOC, then
reorient the easy-axis of the superlattices. Additionally, it enlarges the MAE
of the films via the cooperation with a robust orbital hybridization between
the Ir and Mn atoms. Our results indicate that the tricolor superlattices
consisting of 3d and 5d oxides provide a powerful platform to study the MA and
develop oxide-based spintronic devices.
