Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.59: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Origin of high Neel temperatures in Tc perovskites — Jernej Mravlje1,2,3, Markus Aichhorn4, and •Antoine Georges1,2 — 1College de France, Paris, France — 2Ecole Polytechnique, Palaiseau, France — 3Josef Stefan Institue, Ljubljana, Slovenija — 4TU Graz, Austria
Very recently, antiferromagnetism persisting to high temperatures exceeding 1000K was discovered in Tc perovskites. Usually, robust magnetism is associated to 3d transition metal oxides, moreover in 4d oxides magnetism is rarely found. Here we describe results of LDA+DMFT calculation of electronic structure of two cubic perovskites, SrMnO3 and SrTcO3. The Neel temperature of SrTcO3 is found 4 times larger, in agreement with experiment. Smaller Tc moment is reproduced aswell. We show that the distinction between the two materials is that Tc is far more on the itinerant side, and found in the immediate proximity to the metal-insulator transition in the paramagnetic state. Accordingly, the dependence of Neel temperature on pressure is very weak in strong violation of the Bloch's law.