Tuning the crystallographic orientation and magnetic properties of multiferroic CuO epitaxial film on single crystalline SrTiO₃ substrates

Abstract

We report a comparative study between the crystal structure and magnetic properties of multiferroic epitaxial CuO thin films grown on (001) and (110) oriented SrTiO₃ substrates. CuO thin films were successfully grown along the [010] direction, which is also the direction of their ferroelectric polarization, on (110) oriented SrTiO₃ substrates. We correlate our structural findings with the magnetic properties. It was observed that the heterostructure with the CuO film grown along the [010] direction shows distinct anomalies in the temperature dependent magnetization plot at 213 K and 230 K, whereas no such anomaly was observed in the case of the heterostructure grown on the (001) SrTiO₃ substrate with the [111] CuO film. Buffered MgO layers were used between the CuO layer and the substrate to improve the crystalline quality of the CuO film