Variable Valence of Ce and Pr in Liquid Alloys with Fe, Co, and Ni

Abstract

The paramagnetic susceptibility and the electrical resistivity of liquid alloys Ce, Pr-Fe, Co, Ni are measured and compared with calculations based on Edwards expressions and on the Ziman theory in t-matrix approximation. In rare-earth-rich alloys the valence of Ce and P r is found to increase monotonously with increasing concentration of the 3d metal. Above a critical concentration the valence remains constant. Many investigations have been devoted to the problem of intermediate valence of rare-earth metals (REM) in solid alloys. Until now, no data on the valence of liquidphase lanthanoids, and in particular, on that of alloys containing 3d transition metals have been reported yet. Unfortunately, the application of direct methods of measurements in this temperature range is impeding. However, data on the valence of the constituents can be obtained from the study of the temperature and concentration dependences of the physical properties of melts, and their comparison with estimates using the valence as an adjustable parameter.The results of our investigations of the magnetic susceptibility and the specific electrical resistivity of Fe, Co, and Ni containing Ce and Pr will be discussed below.