PHASE STABILITY AND SOME PHYSICAL PROPERTIES OF THE YbCu5-RELATED INTERMETALLICS
K. Yoshimura1, N. Tsujii1, J. He1, T.Kawabata1 , H. Michor2, K. Kreiner2, G.
Hilscher2, T. Miyano3, M. Kato1 and K. Kosuge1
1Division
of Chemistry, Graduate School of Science, Kyoto University, Kyoto
606-8502, Japan
2Institute für Experimentalphysik, Technishe
Universität Wien, Wiedner Hauptstrasse 8-10/131, A-1040 Wien,
Austria
3Inorganic
Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91
Stockholm, Sweden
In the rare earth RE-Cu systems, the RECu5 intermetallics crystallize in CaCu5-type hexagonal structure or AuBe5-type cubic structure. In this paper, we concentrate on the YbCu5-related intermetallics. We have been studying the YbCu5-xMx systems with hexagonal (M=Al, Ga) and cubic (Ag, Au, Pd, In, Tl, Cd) structures from a view point of solid state physics and chemistry[1]. For the latter systems, mixed phases appears in the composition range 0²x²0.1, i.e. [Yb2Cu9 [2](C'phase) + Yb2Cu13 [3](H'phase)]. An alloy with the nominal composition YbCu5 was prepared by Ar arc melting and then annealed at 750C. X-ray powder diffraction pattern of this sample showed that the sample consisits of C' and H' phases, i.e.two phase mixtures: YbCu5 phase does not exist under ambient pressure against the paper of A.Iandelli & A. Palenzona [4], which clearly indicates the existence of YbCu5 phase.
Recently, our group succeeded in preparing cubic YbCu5 phase under the pressure of 1.5GPa at 900C[1]. The width of X-ray powder diffraction peaks of this cubic phase is very broad, more than two times of that of usual samples. We are now investigating the structure of ìcubic YbCu5î from a microscopic point of view by use of TEM, SEM and EDX etc.. By the discovery of existence of cubic YbCu5, the physical properties of substitutional systems YbCu5-xMx have been promoted better understanding through the whole composition range 0²x²1.
We expect to present the nature
of "cubic YbCu5" and the physical properties
of YbCu5-related compound.
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He, M. Kato, K. Kosuge, H. Michor, K. Kreiner, G. Hilscher, T.
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Nissen, R. Wessicken: J. Phys. Condens. Matter 8(1996)
4485- 4493
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333-335