Strong magnetic response regulated by layer-stacking perturbations in an Aurivillius-phase oxide

Abstract

An excellent platform to investigate the role of layer-perovskite stacking in tuning magnetic properties was constructed in Aurivillius-type Bi11Fe2.9Co0.1Ti6O33 by A-site non-magnetic Sm-doping. Nanoscale layer-stacking evolution was clearly observed from the close-order intergrowth of the 4- and 5-layer slabs to the low-average-n mixed-layer phase, as increasing the doping-level. Such layer-stacking perturbations induced a coexistence between disorder mixed-layers and local order-layers, giving rise to strong ferromagnetic-antiferromagnetic interactions at lower temperatures reflecting in larger magnetic coercive fields (2Ec ∼ 0.8 T) and higher remanent magnetization. Based on X-ray absorption spectra, the anomalous magnetic responses at 50–150 K may be ascribed to simultaneous strengthening of iron 3d-state vacancies and metal–oxygen orbital hybridization, generating the large local ferromagnetic-state into intrinsic antiferromagnetic-state, thus achieving a strong coupling.