Magneto-optical properties of La2/3Sr1/3MnO3 ultrathin films
  Pulse laser deposited La2/3Sr1/3MnO3 ultrathin films on SrTiO3 substrates were characterized by polar and longitudinal Kerr magneto-optical spectroscopy. An agreement between experimental and theoretical spectra was achieved for a 10.7 nm thick film, while a distinction in the Kerr effect amplitudes was obtained for a 5 nm thick film. This points to the slight suppression of ferromagnetism by interface effects. Nevertheless, the room temperature ferromagnetism of the 5 nm thick film was clearly demonstrated. All the studied films exhibit magneto-optical properties similar to single crystals and thick films, which confirms a fully developed perovskite structure even at 5 nm. 
M. Veis, M. Zahradnik, R. Antos, S. Visnovsky, Ph. Lecoeur, D. Esteve,   S. Autier-Laurent, J.-P. Renard and P. Beauvillanin
cond-mat.mtrl-sci physics.optics