Magnetic properties and thermal expansion of YbGa$_x$Ge$_{2-x}$ (0.9 <= x <= 1.5)

TL;DR

This study investigates how the composition affects the valence state and thermal expansion in YbGa$_x$Ge$_{2-x}$, revealing stable Yb2+ states and typical thermal contraction without zero thermal-expansion.

Contribution

It provides detailed analysis of composition-dependent valence, magnetic, and thermal properties in YbGa$_x$Ge$_{2-x}$, challenging previous reports of zero thermal-expansion.

Findings

Yb remains in a stable 2+ state across the studied range

Lattice constants decrease monotonically with temperature

No evidence of zero thermal-expansion in the system

Abstract

The composition dependence of the Yb valence and of the thermal expansion have been studied in the YbGa$_x$Ge$_{2-x}$ system. X-ray diffraction reveals that single-phased samples isostructural to YbGaGe are obtained in the range of 0.9 <= x <= 1.5. The magnetic susceptibility shows that the systems are almost nonmagnetic below room temperature, indicating a stable Yb2+ state for the x range 0.9 <= x <= 1.5. The lattice constants as well as the lattice volume of these systems are found to decrease monotonically with decreasing temperature, suggesting the absence of zero thermal-expansion previously reported for YbGaGe.