Non-uniform magnetization in LaAlO3/SrTiO3 superlattices.
Abstract
Recently, Brinkman et al., [Nature 6, 493 (2007)] reported magnetism induced at the interface between LaAlO3 (LAO) and SrTiO3 (STO)inferred from transport measurements. They found the magnetization to be greatly enhanced at low temperatures (i.e., liquid He temperature) and by application of high (10+ T) fields. We report polarized neutron reflectometry measurements of the magnetization depth profile of two LAO/STO superlattices with the same number of bilayer repeats. For low temperatures and a field of 11 T, the intensities of the superlattice Bragg reflections for both samples exhibited a dependence upon neutron beam polarization. The spin dependence was much weaker at small field (and low temperature) and disappeared altogether at 11 T and 300 K. These observations demonstrate that the magnetization depth profile has the period of the LAO/STO superlattice. The neutron spin dependence was more pronounced for the sample with a thin LAO layer compared to one with a thick LAO layer, suggesting that the magnetism may be interfacial in origin.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2009
- Bibcode:
- 2009APS..MARQ30003F