Incorporation of cobalt ions into magnetoelectric gallium ferrite epitaxial films: Tuning of conductivity and magnetization

Thin films of Ga_0.6Fe_1.4O₃ show ferrimagnetism with a transition temperature at around 360 K but suffer from large charge conduction. Substituting Fe²⁺ with non-magnetic Mg²⁺ ions reduces the charge conduction but also lowers the magnetic transition temperature. Doping Ga_0.6Fe_1.4O₃ thin films with magnetic Co²⁺ ions leads to a similar reduction in the charge conduction, which is significant by two orders of magnitude, and, on the other hand, does not lead to any modification of the ferrimagnetic transition. The remnant magnetization of the leakage currents free Co-doped Ga_0.6Fe_1.4O₃ thin films is of 53 emu cm^-3 at 300 K. These films, therefore, are promising materials with potential uses in magnetoelectric and multiferroic devices.