Magnetoresistive effect in the cobalt-doped bismuth ferrite films

Romanova, O. B.; Aplesnin, S. S.; Sitnikov, M. N.; Udod, L., V; Begisheva, O. B.; et al. Journal Of Materials Science-materials In Electronics.

Bismuth ferrite flms have been synthesized by the burst-mode deposition of the BiFe0.8Co0.2O3 solid solutions onto object glasses. The surface morphology of the BiFe0.8Co0.2O3 flms has been examined. The efect of electron doping implemented by substitution of cobalt for iron in the BiFe0.8Co0.2O3 flms on their magnetic, electrical, and galvanomagnetic properties has been investigated at temperatures of 77‒600 K in magnetic felds of up to 12 kOe. The negative magnetoresistance has been observed, which changes its sign in the region of formation of magnetically heterogeneous states and attain its maximum value above room temperature. It has been established that the magnetoresistance is caused by the competition of electron hoppings and localization of electrons in a magnetic feld. Using the Hall measurements, the carrier type has been determined. A model of the change in the curriers sign upon heating due to the shift of the chemical potential relative to the impurity subband has been proposed.