Voltage-induced reversible and irreversible changes in the magnetic coercivity of Fe, Co/ZnO heterostructures

This study investigates the magnetic coercivity of heterostructures composed of a transition metal (Fe and Co) and a semiconductor (ZnO). An enhancement in the magnetic coercivity is observed which is due to direct current heating-induced oxidation at the interface. Depth-profiling X-ray photoemission spectroscopy observations confirm oxide formation at the interface due to annealing. It is shown that magnetic coercivity of heterostructures monotonically decreased as a relatively small voltage is applied and its reversibility is demonstrated by cyclically changing the bias voltage.