STUDIES OF LOW-TEMPERATURE SPECIFIC-HEATS AND THERMAL-CONDUCTIVITIES OF THE CSCL-TYPE (PR1-XNDX)AG 0-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-1) INTERMETALLIC COMPOUNDS - APPLICATION TO REGENERATOR MATERIALS

The CsCl-type intermetallic compound can be formed over a whole compos ition range 0 less than or equal to x less than or equal to 1 in the c hemical formula (Pr1-xNdx)Ag. The low temperature specific heat and th ermal conductivity were measured over the temperature range 2-25K to e xamine whether a series of intermetallic compounds can be used as rege nerator materials in the GM- or Stirling-cycle refrigerator. The volum etric specific heats of samples in which x = 0 and 0.1 were found to e xceed 1J/(K cm(3)) in the vicinity of 10K whereas that of samples with x = 1.0 reached almost 1.5 J/(K cm(3)) above 20K, and is claimed to b e the largest among those reported so far in the respective temperatur e ranges. The thermal conductivity of these compounds is found to be 5 -10 times higher than that of Er3Ni. The occurrence of a large magneti c specific heat is due to high degeneracies of the ground states. Judg ing from the present thermal and magnetic studies, we claim that a ser ies of (Pr1-xNdx)Ag compounds can be used as good regenerator material s in the temperature range 10-25 K.