Nature of weak magnetism in SrTiO3/LaAlO3 multilayers

  • Z. Salman*
  • , O. Ofer
  • , M. Radovic
  • , H. Hao
  • , M. Ben Shalom
  • , K. H. Chow
  • , Y. Dagan
  • , M. D. Hossain
  • , C. D.P. Levy
  • , W. A. MacFarlane
  • , G. M. Morris
  • , L. Patthey
  • , M. R. Pearson
  • , H. Saadaoui
  • , T. Schmitt
  • , D. Wang
  • , R. F. Kiefl
  • *Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

We report the observation of weak magnetism in superlattices of LaAlO 3/SrTiO3 using β-detected nuclear magnetic resonance. The spin lattice relaxation rate of Li8 in superlattices with a spacer layers of 8 and 6 unit cells of LaAlO3 exhibits a strong peak near ∼35 K, whereas no such peak is observed in a superlattice with spacer layer thickness of 3 unit cells. We attribute the observed temperature dependence to slowing down of weakly coupled electronic moments at the LaAlO 3/SrTiO3 interface. These results show that the magnetism at the interface depends strongly on the thickness of the spacer layer, and that a minimal thickness of ∼4-6 unit cells is required for the appearance of magnetism. A simple model is used to determine that the observed relaxation is due to small fluctuating moments (∼0.002μB) in the two samples with a larger LaAlO3 spacer thickness.

Original languageEnglish
Article number257207
JournalPhysical Review Letters
Volume109
Issue number25
DOIs
StatePublished - 20 Dec 2012
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy

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