Electrode optimization for improved magnetoelectric switching behavior in ultra-thin Cr₂O₃ films

Voltage-controlled switching of magnetization is manifested through exchange bias (EB) and promises non-volatile spintronic memory and logic devices. The influence of seed layer properties on the morphology and dielectric properties of thin films of the magnetoelectric antiferromagnet chromia (α-Cr₂O₃) is investigated. The films were grown on metallic electrodes Pd (111) and Pt (111) or on metallic oxide film V₂O₃. Correlation between nanoscale structure and electrical properties of chromia, was probed by conductive Atomic-Force-Microscopy (C-AFM). Whereas films grown on elemental metal substrates showed either leakage pathways (Pd) or partially mitigated leakage (Pt), a remarkable suppression of leakage and surface defects was found in films formed on V₂O₃. X-ray analyses attribute these differences to the presence of in-plane rotational domains in the films grown on Pd substrates, a feature that is reduced in films grown on Pt and absent in films grown on V₂O₃. This growth strategy demonstrates a vastly improved magnetoelectric switching characteristics in 20 nm thin Cr₂O₃ films.