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arXiv · 1401.1871

Persistent Optically Induced Magnetism in Oxygen-Deficient Strontium Titanate

W. D. Rice·P. Ambwani·M. Bombeck·J. D. Thompson·C. Leighton·S. A. Crooker
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Abstract

Strontium titanate (SrTiO$_3$) is a foundational material in the emerging field of complex oxide electronics. While its electronic and optical properties have been studied for decades, SrTiO$_3$ has recently become a renewed materials research focus catalyzed in part by the discovery of magnetism and superconductivity at interfaces between SrTiO$_3$ and other oxides. The formation and distribution of oxygen vacancies may play an essential but as-yet-incompletely understood role in these effects. Moreover, recent signatures of magnetization in gated SrTiO$_3$ have further galvanized interest in the emergent properties of this nominally nonmagnetic material. Here we observe an optically induced and persistent magnetization in oxygen-deficient SrTiO$_{3-δ}$ using magnetic circular dichroism (MCD) spectroscopy and SQUID magnetometry. This zero-field magnetization appears below ~18K, persists for hours below 10K, and is tunable via the polarization and wavelength of sub-bandgap (400-500nm) light. These effects occur only in oxygen-deficient samples, revealing the detailed interplay between magnetism, lattice defects, and light in an archetypal oxide material.

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W. D. Rice, P. Ambwani, M. Bombeck, J. D. Thompson, C. Leighton, S. A. Crooker. 2014-01-09. Persistent Optically Induced Magnetism in Oxygen-Deficient Strontium Titanate. https://doi.org/10.1038/nmat3914

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