Pressure-induced valence change of Eu in Eu(Pd0.8Au0.2)2Si2: Collapse of magnetic order.

Abstract

We report the first observation of a pressure-induced breakdown of a magnetically ordering ${\mathrm{Eu}}^{2+}$ ($J=\frac{7}{2}$) state to a nonmagnetic intermediate-valent state in antiferromagnetically ordered Eu(${\mathrm{Pd}}_{0.8}$${\mathrm{Au}}_{0.2}$)$_{2}\mathrm{Si}_{2}$. The experimental results allow us to determine the limits of the range of the Eu mean valence of $2.0<~\overline{v}<~2.2$ at 4.2 K, over which magnetic order and intermediate valence can coexist.