Magnetoresistive effect in the cobalt-doped bismuth ferrite films

Bismuth ferrite films 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 films has been examined. The effect of electron doping implemented by substitution of cobalt for iron in the BiFe0.8Co0.2O3 films on their magnetic, electrical, and galvanomagnetic properties has been investigated at temperatures of 77‒600 K in magnetic fields 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 field. 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.