Electric field controlled magnetic exchange bias and magnetic state switching at room temperature in Ga-doped α-Fe2O3 oxide

We report magnetoelectric properties in Ga-doped α-Fe2O3 system in rhombohedral phase. The material is a canted ferromagnet at room temperature. The electric field controlled magnetic state switching provided a direct evidence of magneto-electric coupling in Ga-doped α-Fe2O3 system. At the first time, we report the unexplored electric field controlled magnetic state switching both in α-Fe2O3 and in Ga-doped α-Fe2O3 system. The response of magnetic state in Ga-doped α-Fe2O3 system under electric field is characteristically different from that in α-Fe2O3. The (un-doped) α-Fe2O3 system does not show electric field controlled magnetic exchange bias shift along magnetic field axis, unlike an extremely high electric field induced magnetic exchange bias shift up to the tune of 1120 Oe (positive) in Ga-doped α-Fe2O3 system. Moreover, the switching of magnetic state is highly sensitive to ON and OFF modes of the applied electric voltage, as well as to the change of polarity during in-field magnetic relaxation experiments. The switching of magnetic state to upper level for positive electric field and to down level for negative electric field excitation confirms a sufficiently strong coupling between electric and magnetic orders in Ga-doped hematite system. Such smart material in single phased lattice structure, very few in nature, is of increasing demand in today's technology for the multifunctional applications in next generation magnetic sensor, switching, non-volatile memory and spintronic devices.