Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 44: Poster Session Correlated Electrons
TT 44.54: Poster
Donnerstag, 17. März 2011, 10:00–13:00, P1
Doping dependence of collective spin states in LaCoO3 — •A. Alfonsov1, E. Vavilova1,2, V. Kataev1, A. Podlesnyak3, E. Pomjakushina4, and B. Büchner1 — 1IFW Dresden, D-01171 Dresden, Germany — 2Zavoisky Physical Technical Institute, RAS, 420029 Kazan, Russia — 3Oak Ridge National Laboratory, P.O. BOX 2008 MS6494 Oak Ridge TN 37831-6494, USA — 4ETH Zurich and Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
We have shown recently that a small Sr doping of LaCoO3 yields the spin-state polaron with a big spin value and substantial spin orbital
coupling [1]. The Sr for La substitution provides the hole doping due to different valency of Sr and La. In addition, it gives rise to a distortion
of the crystal field around the doped ion due to the mismatch of ionic radii. The present work is aimed to discriminate between the effect of the
charge (hole- or electron) doping and the effect of structural distortion. For that we have carried out a comparative high field electron spin-
(ESR), nuclear magnetic resonance (NMR) and static magnetization study of lightly doped samples of La0.998A0.002CoO3 (A = Sr, Ca, Y,
Sn, Ce). We will discuss the role of the heterovalent hole- (Sr2+, Ca2+) and electron doping (Sn4+, Ce4+) as well as the
homovalent doping with Y3+ (rY3+ion ≪ rLa3+ion) for the formation of the spin-state polaron in LaCoO3.
A. Podlesnyak et al., Phys. Rev. Lett. 101, 247603 (2008)