Role of defects in BiFeO3 multiferroic films and their local electronic structure by x-ray absorption spectroscopy

Abstract

Present study reports the role of defects in the electrical transport in BiFeO3 (BFO) multiferroic films and its local electronic structure investigated by near-edge X-ray absorption fine structure. Defects created by high energy 200 MeV Ag+15 ion irradiation with a fluence of ∼5 × 1011 ions/cm2 results in the increase in structural strain and reduction in the mobility of charge carriers and enhancement in resistive (I-V) and polarization (P-E) switching behaviour. At higher fluence of ∼5 × 1012 ions/cm2, there is a release in the structural strain due to local annealing effect, resulting in an increase in the mobility of charge carriers, which are released from oxygen vacancies and hence suppression in resistive and polarization switching. Near-edge X-ray absorption fine structure studies at Fe L3, 2- and O K-edges show a significant change in the spectral features suggesting the modifications in the local electronic structure responsible for changes in the intrinsic magnetic moment and electrical transport properties of BFO.