Improvement from discrete to uniform wetting of organic perovskite on ferromagnetic metals through a heterointerface

Considerable effort has been expended on the combination of a ferromagnetic layer with a perovskite film for application in light-controlled spintronic devices. However, to achieve such combinations, gaining control over the interface quality and the interaction between the ferromagnetic and perovskite layers is crucial. Studies have observed discrete distributions of organic perovskite (methylammonium lead bromide, MAPbBr₃) films, which self-assemble into nanodiscs, on iron–palladium alloy films. To achieve uniform wetting, we proposed the insertion of an ultrathin heterointerface of an aluminum oxide or graphene layer between perovskite and metal films. Through atomic force microscopy and scanning electron microscopy, we observed that the derived MAPbBr₃ coating successfully formed a continuous and dense layer without voids, with its roughness fluctuations being within a few nanometers. Magneto-optical Kerr effect measurement for material characterization revealed that the perovskite films had a negligible capping effect on magnetism. These results provide insight into the potential technological applications of perovskite/metal heterostructures.