Thermal Expansion and Electrical Resistivity of EuNi₂(Si_1-xGe_x)₂

Abstract

The thermal expansion and temperature dependence of electrical resistivity were measured for EuNi 2 (Si 1- x Ge x ) 2 , which shows a valence transition against temperature in 0.5≤ x ≤0.82. A first-order phase transition was observed in the temperature dependence of the lattice parameters of x =0.79 and 0.82, while the lattice parameters vary continuously with temperature for x ≤0.70. The temperature dependence of electrical resistivity shows a peak at the valence transition temperature. The origin of the peak is discussed on the basis of the dynamic alloy model.