Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.34: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Unusual electronic and magnetic properties of intermetallic antiperovskites — •Claire Loison, Andreas Leithe-Jasper, and Helge Rosner — Max Planck Institut für Chemische Physik fester Stoffe, Nöthnitzerstrasse 40, 01187 Dresden, Germany
In the last years, cubic perovskites XYT3 (X=Mg,Cu,La..., Y=B,C,N... and T a transition metal) have received considerable attention because of many unusual physical properties caused by different competing interactions. Examples are the recently discovered superconductor MgCNi3 or the non-collinear magnet CuNMn3. Here, we present a systematic study of a series of antiperovskites (RBxPd3 where R is a rare-earth metal, and x varies between 0 and 1) using density functional theory (DFT) electronic structure calculations within the local spin density approximation (LSDA). To investigate the role of possible strong Coulomb repulsion we applied as well LSDA+U. We investigate the effects of pressure and doping on the electronic properties and magnetism. In order to interpret the discrepancies between the results on the lattice constants of LaBxPd3 as published by Dhar et al.[1] and our theoretical calculations, we examined this compound experimentally too. The insertion of boron in LaPd3 (a=4.1862(1)Å) could not be detected, but the exposure to oxygen resulted in an increased lattice constant of a=4.2368(2)Å close to the value published in [1]. They report a lattice constant independent of x; according to our calculations, it should increase almost linearly and substantially with x. Thus, our results are inconsistent with the formation of LaBxPd3.
[1] Dhar et al. Mat. Res. Bull. 16 1557 (1981).