Ion-irradiation–induced relaxation of tensile strain and change in directionality of magnetic domains in BaFeO3−δ thin films

Abstract

Perovskite (BFO) thin films , deposited on MgO (001) single-crystal wafers, were irradiated by ion beams of: i) 200 MeV (Series-1) and ii) 100 MeV (Series-2). These films are investigated for structural, morphological, and magnetic properties. There is a systematic variation in the morphology of the BFO films with increasing beam fluence, resulting in relaxation of tensile strain. The Magnetic Force Microscopy (MFM) images show stripe-like magnetic domains of the remanent magnetization, which were studied by Fast Fourier Transformation. With increasing ion fluence, the formation of stripe domains gradually changes the direction from one crystallographic plane to two planes. MFM patterns of Series-2 show gradually diffusing directionality of magnetic domains with increasing ion fluence. The simultaneous and systematic changes in strain and magnetic properties due to ion irradiation indicate the correlated properties of BFO thin films.