Voltage controlled magnetism in Cr2O3 based all-thin-film systems

•Progress on voltage controlled exchange bias in Cr2O3/CoPd all thin film heterostructure.•Read out of voltage controlled boundary magnetization in ultrathin Cr2O3/Pt Hall bar devices.•Magneto-optical detection of isothermally switched antiferromagnetic domain states.•Evidence for antiferromagnetic multi domain state through magneto-optical measurements. Voltage-control of exchange biases through active selection of distinct domain states of the magnetoelectric and antiferromagnetic pinning layer is demonstrated for Cr2O3/CoPd heterostructures. Progress and obstacles towards an isothermal switching of exchange bias are discussed. An alternative approach avoiding exchange bias for voltage-controlled memory exploits boundary magnetization at the surface of Cr2O3 as voltage-controlled state variable. We demonstrate readout and switching of boundary magnetization in ultra-thin Cr2O3/Pt Hall bar devices where reversal of boundary magnetization is achieved via magnetoelectric annealing with simultaneously applied ±0.5 V and 400 mT electric and magnetic fields.