Impurity Effect of Lanthanum on the γ–α Transition Temperature and Pressure of Ce Metal

Abstract

The γ–α transition pressure (P_γ–α), temperature (T_γ–α), and critical point (P_c, T_c) of Ce_1−xLa_x alloys (x=0.0∼0.03) were determined by electrical resistivity measurements under pressure up to 10 kbar at temperatures between 50 K and 300 K. A nonlinear dependence of T_γ–α on pressure was confirmed for x=0.0 and 0.02 in agreement with the theory for x=0.0 by Miyamoto and Nagamiya (MN) rather than that by Ramirez and Falicov (RF). The impurity effects of lanthanum on P_γ→α, T_γ→α, and T_α→γ were determined experimentally: ∂P_γ→α⁄∂x=(0.37±0.06)kbar/(at.%La), ∂T_γ→α⁄∂x=−(12.5±1)K/(at.%La) and ∂T_α→γ⁄∂x=−(12±1)K/(at.%La) respectively. These experimental results were found to be in qualitative agreement with the calculated results by an extension of the MN theory.