The valence state of Yb ion in YbIn[Au.sub.2] compound at high pressure determined by x-ray diffraction and x-ray absorption near edge structure measurements

The valency of Yb ion in YbIn[Au.sub.2] is determined by the Yb [L.sub.III]-edge x-ray absorption near edge structure spectroscopy at high pressure and the lattice compression curves of YbIn[Au.sub.2] and LuIn[Au.sub.2] compounds are observed by the x-ray diffraction measurement using intense synchrotron radiation x-ray sources. The results have shown that the valence state of Yb ion in YbIn[Au.sub.2] is strongly correlated to the unit-cell volume so that the magnetic 4[f.sup.13] state is stabilized at high pressure.