March 31, 2014
- In collaboration with the group of Scott Crooker at Los Alamos National Lab and Greg Haugstad of the CSE Characterization Facility, CEMS graduate student Palak Ambwani and faculty member Chris Leighton have recently reported a remarkable finding in complex oxides. The team discovered that illuminating the oxide semiconductor strontium titanate with circularly polarized light can induce magnetism in this otherwise non-magnetic material. Most surprisingly, at cryogenic temperatures the induced magnetism is retained even after turning off the illumination, creating the ability to optically write, store, and read information (refer to image). The effect occurs only in samples deliberately prepared to have missing oxygen ions (vacancies), implicating a defect complex. Work is underway to understand the nature of this defect, potentially the key to room temperature operation. The work, "Persistent optically induced magnetism in oxygen-deficient strontium titanate?", was recently published in Nature Materials.
Related Link: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat3914.html