Nature of weak magnetism in SrTiO3/LaAlO3 multilayers
  We report the observation of weak magnetism in superlattices of LaAlO3/SrTiO3 using beta-detected nuclear magnetic resonance. The spin lattice relaxation rate of 8 Li 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 LaAlO3/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 (~0.002 muB) in the two samples with a larger LaAlO3 spacer thickness. 
Z. Salman, O. Ofer, M. Radovic, H. Hao, K. H. Chow, M. D. Hossain, C.   D. P. Levy, W. A. MacFarlane, G. M. Morris, L. Patth...
cond-mat.mtrl-sci cond-mat.mes-hall