Resistive dependence of magnetic properties in nonvolatile Ti/Mn:TiO2/SrTi0.993Nb0.007O3/Ti memory device

We report the relationship of the magnetic properties of the Mn-doped TiO2(Mn:TiO2) thin film on SrTi0.993Ti0.007O3 substrate to the different resistance states of the Ti/Mn:TiO2/Nb:SrTiO3/Ti device. Initially, the device showed paramagnetic behavior without applying voltage. When the device was switched to low resistance state after applying a positive voltage, robust ferromagnetism was observed. In contrast, when a negative voltage was applied to switch to high resistance state, the device exhibited weak ferromagnetism. This electrically controllable ferromagnetism should be attributed to the tunability of oxygen-vacancy concentration in the Mn:TiO2 film by electric field.