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Pressure-induced valence changes in mixed-valent systems

Chandran, Leena and Krishnamurthy, HR and Ramakrishnan, TV (1992) Pressure-induced valence changes in mixed-valent systems. In: Journal of Physics: Condensed Matter, 4 (34). pp. 7067-7094.

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Mixed-valent systems based on Ce, Sm, Eu and Yb exhibit a wide range of behaviour with respect to valence changes under the application of pressure. We present a semi phenomenological model for this behaviour based on competition effects between the usual elastic energy cost and the magnetic energy gain due to valence fluctuations. For the latter we use a mean-field Andenon lattice description and incorporate the effects of pressure by introducing a volume dependence to the Anderson model parameters $\epsilon_f$ and $\Delta$. In contrast to existing models such as the Kondo Volume Collapse theory of Allen and Martin, which describes magnetic to non-magnetic transitions without sizable valence change $(e.g. \gamma-Ce\rightarrow \alpha-Ce)$, the Anderson lattice model developed here dascribes systems with both small and large valence changes the transition can be continuous $(e.g. EuPd_2Si_2)$ or discontinuous ($EuPd_2Si_2$ alloyed with Au).

Item Type: Journal Article
Publication: Journal of Physics: Condensed Matter
Publisher: Institute of Physics
Additional Information: Copyright of this article belongs to Institute of Physics.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 05 Sep 2006
Last Modified: 19 Sep 2010 04:30
URI: http://eprints.iisc.ac.in/id/eprint/8139

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