Bulk-like dielectric and magnetic properties of sub 100 nm thick single crystal CrO films on an epitaxial oxide electrode.

The manipulation of antiferromagnetic order in magnetoelectric CrO using electric field has been of great interest due to its potential in low-power electronics. The substantial leakage and low dielectric breakdown observed in twinned CrO thin films, however, hinders its development in energy efficient spintronics. To compensate, large film thicknesses (250 nm or greater) have been employed at the expense of device scalability. Recently, epitaxial VO thin film electrodes have been used to eliminate twin boundaries and significantly reduce the leakage of 300 nm thick single crystal films. Here we report the electrical endurance and magnetic properties of thin (less than 100 nm) single crystal CrO films on epitaxial VO buffered AlO (0001) single crystal substrates. The growth of CrO on isostructural VO thin film electrodes helps eliminate the existence of twin domains in CrO films, therefore significantly reducing leakage current and increasing dielectric breakdown. 60 nm thick CrO films show bulk-like resistivity (~ 10 Ω cm) with a breakdown voltage in the range of 150-300 MV/m. Exchange bias measurements of 30 nm thick CrO display a blocking temperature of ~ 285 K while room temperature optical second harmonic generation measurements possess the symmetry consistent with bulk magnetic order.