In this work, we study the time- and temperature-dependence of optically induced magnetization in bulk crystals of slightly oxygen-deficient SrTiO3−δ using an optically coupled SQUID magnetometer. We find that a weak (∼5×10−7~emu) but extremely long-lived (hours) magnetic moment can be induced in SrTiO3−δ at zero magnetic field by circular-polarized sub-bandgap light. We utilize this effect to demonstrate that SrTiO3−δ crystals can be used as an optically addressable magnetic memory by writing and subsequently reading magnetic patterns with light. The induced magnetization is consistent with that of a polarized ensemble of independent oxygen-vacancy-related complexes, rather than from collective or long-range magnetic order.
@article{arxiv.1407.4157,
title = {Revealing Optically Induced Magnetization in SrTiO$_3$ using Optically Coupled SQUID Magnetometry and Magnetic Circular Dichroism},
author = {W. D. Rice and P. Ambwani and J. D. Thompson and C. Leighton and S. A. Crooker},
journal= {arXiv preprint arXiv:1407.4157},
year = {2014}
}