Spin-polarized oxygen hole states in cation-deficient 1-x xG. Papavassiliou1, M. Pissas1, M. Belesi1, M. Fardis1, M. Karayanni1, J. P. Ansermet2, 3, D. Carlier3, C. Dimitropoulos3 and J. Dolinsek4
1 Institute of Materials Science, NCSR Demokritos 153 10 Aghia Paraskevi, Attiki, Greece
2 Department of Physics, University of Illinois - Urbana, IL 1801, USA
3 Institut de Physique Experimentale, EPFL-PH-Ecublens 1015-Lausanne, Switzerland
4 Josef Stefan Institute - Jamova 39, 61111 Ljubljana, Slovenia
received 12 May 2004; accepted in final form 15 September 2004
published online 13 October 2004
We report on NMR evidence about a novel effect in 1-x x systems with cation deficience. We show that in the low- -doping regime, these systems exhibit a very strong hyperfine field at certain nuclear sites, which is not present in the stoichiometric compounds. Comparison of our NMR results with recent X-ray absorption data at the K-edge, suggests the formation of a spin-polarized hole arrangement on the 2p oxygen orbitals as the origin of this effect.
75.47.Lx - Manganites.
76.60.-k - Nuclear magnetic resonance and relaxation.
75.47.Gk - Colossal magnetoresistance.
© EDP Sciences 2004