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E. Gratz, K. Hense, A. Hoser, N. Stüsser, V. Paul-Boncour, A. Markosyan:
"Temperature induced metamagnetism in ErCo₃ studied by neutron diffraction";
Poster: 52. Jahrestagung der ÖPG, Leoben; 23.09.2002 - 26.09.2002.

The RCo3 compounds crystallize in the rhombohedral PuNi3-type structure (space group R-3m) with two nonequivalent rare earth (R) sites and three Co-sites, (Co1: 3b, Co2: 6c, Co3:18h, Er1: 3a and Er2: 6c).
Magnetization measurements in high magnetic fields of YCo3 (a weak itinerant ferromagnet with TC=300 K) revealed two step like changes of the Co-sublattic magnetization at 60 T and 82 T (metamagnetic transitions) [1]. It will be shown that in the isostructural ErCo3 compound (TC = 401 K) a temperature induced metamagnetic transition exists at 100 K in zero external magnetic field mainly due to the increasing molecular field in the Er sublattice when lowering the temperature. Neutron powder diffraction studies on the E6 spectrometer at HMI showed that the Co-moments on two of the three Co-sites increases by about 100 % below 100 K. This changes of the itinerant Co moments at the metamagnetic transition is accompanied by a tremendous increase of the unit cell volume (dV/V_0.004). We report about the pattern refinement and give a qualitative discussion of the mechanism behind this metamagnetic transition in ErCo3 [2].

[1] T. Goto, H. Aruga Katori, T. Sakakibara and M. Yamaguchi, Physica B 177, 255 (1992)
[2] E. Gratz, A. S. Markosyan, V. Paul-Boncour, A. Hoser, N. Stuesser, I. Yu. Gaidukova, V. E. Rodimin,
Temperature Induced Itinerant Electron Magnetism in ErCo3 Studied by Neutron Diffraction, to be published in Journal of Applied Physics A