Electric-Field-Induced Change of the Magnetoresistance in the Multiferroic Spin-Valve Based on ${\hbox {BiFeO}}_{3}$ Film

The electric-field control of magnetization has many potential applications in magnetic memory storage, sensors, and spintronics. A new multiferroic spin-valve (SV) heterostructure was grown by combining a multiferroic BiFeO₃ (BFO) and a Co₉₀Fe₁₀/Cu/Co₉₀Fe₁₀ spin valve on Pt/Ti/SiO₂/Si substrate. Through the magnetoelectric coupling between a BFO layer and Co₉₀Fe₁₀ layer, the magnetoresistance of SV could be controlled by electric field applied on the BFO layer. The BFO film exhibits an obvious ferroelectric property with a remnant polarization of 17 μC/cm² and a coercive field of 400 kV/cm. The exchange bias of 6 Oe and magnetoresistance (MR) of 1.04% were observed in the heterostructure at room temperature. Moreover, an electric-field-induced change of MR was demonstrated when we employed 0.5- and -0.5-V voltage between top and bottom electrode layer. Furthermore, the values of MR of the spin were changed into 0.71% and 0.95%, respectively. This realization of the electric-field-induced change of MR indicates the great potential applications in future functional devices.