Electric field manipulation of transport properties for ultra-thin Fe 70 Ga 30 films on BaZr 0.2 Ti 0.8 O 3 -0.5Ba 0.7 Ca 0.3 TiO 3 films

We demonstrate a memory device with bias electric field-manipulated multilevel resistance states based on ultra-thin and small area Fe 70 Ga 30 (FeGa) films grown on BaZr 0.2 Ti 0.8 O 3 -0.5Ba 0.7 Ca 0.3 TiO 3 (BZT-0.5BCT) ferroelectric films. Studies have shown that BZT-0.5BCT ferroelectric films exhibit good ferroelectric properties with saturated polarization of 11.3 µC/cm 2 and excellent piezoelectric properties with displacement up to 70 Å. A coercive field of 91 Oe is derived from the magnetic hysteresis loop of BZT-0.5BCT/FeGa composite films. Local ferroelectric domain and ferromagnetic domain structures have been probed, which confirm the multiferroicity of the composite films. By applying the bias electric field along the thickness of the films, current–voltage (I–V) behaviors of the FeGa films on the BZT–BCT films can be modulated, and multiple resistance states are generated. Based on the analysis of polarization switching behavior and the electrical transport characteristics, we ascribe this bias voltage modulation of the resistance state to strain-mediated converse magnetoelectric effect, interface bonding effect, and interface charge-co-mediated behaviors. This work suggests a promising approach for exploring multilevel and multifunctional data storage in multiferroic materials.