We report torque magnetometry measurements of an oxide heterostructure consisting of an amorphous Al2O3 thin film grown on a crystalline SrTiO3 substrate (a-AO/STO) by atomic layer deposition. We find a torque response that resembles previous studies of crystalline LaAlO3/SrTiO3 (LAO/STO) heterointerfaces, consistent with strongly anisotropic magnetic ordering in the plane of the interface. Unlike crystalline LAO, amorphous Al2O3 is nonpolar, indicating that planar magnetism at an oxide interface is possible without the strong internal electric fields generated within the polarization catastrophe model. We discuss our results in the context of current theoretical efforts to explain magnetism in crystalline LAO/STO.
@article{arxiv.1409.3194,
title = {Torque magnetometry of an amorphous-alumina/strontium-titanate interface},
author = {S. L. Tomarken and A. F. Young and S. W. Lee and R. G. Gordon and R. C. Ashoori},
journal= {arXiv preprint arXiv:1409.3194},
year = {2014}
}