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H. Michor, M. El-Hagary, E. Bauer, G. Hilscher, P. Rogl:
"Magnetic Properties of RCo₉Si₄";
Vortrag: VIII International Conference on Crystal Chemistry of Intermetallic Compounds, Ivan Franko National University of L´viv, Ukraine; 25.09.2002 - 28.09.2002.

MAGNETIC PROPERTIES OF RCo9Si4

H. Michor, M. El-Hagary, E. Bauer, G. Hilscher1 and P. Rogl2
1Institut für Festkörperphysik, TU Wien, A-1040 Wien, Austria
2Institut für Physikalische Chemie, Universität Wien, A-1090 Wien, Austria

Ternary compounds RCo9Si4 (R = Pr, Gd, Tb and Y) were prepared by high frequency induction melting and subsequent annealing at 1050°C. The formation of the ordered ternary compounds was confirmed by X-ray powder diffraction and electron microprobe analysis. The crystal structure of these compounds is found to be in agreement with the previously reported tetragonal CeNi8.5Si4.5-type with space group I4/mcm, which is related to the cubic NaZn13-type structure [1]. The low temperature properties were studied by specific heat, magnetisation and resistivity measurements. These measurements reveal the onset of ferromagnetic order at Curie temperatures TC varying between 20 and 50 K for RCo9Si4 samples with magnetic rare earth Pr, Tb, Gd and also with non-magnetic Y which appears to disagree with the significantly higher TC~900 K reported by Skolozdra et al. [1]. The difference between these results may origin from the significant composition dependence of TC upon the Co/Si stoichiometry reported by Rao et al. [2].
[1] R.V. Skolozdra et al., J. Alloys and Compounds 296 (2000) 272-275.
[2] G.H. Rao et al., Appl.Phys.Lett. 64 (1994) 1650-1652.