MAGNETIC AND ELECTRICAL-PROPERTIES OF R7PD3 (R = LA, CE, PR, ND AND SM)

AC magnetic susceptibility, magnetization, electrical resistivity, the pressure effects on them and thermal expansion have been measured for R7Pd3 compounds (R = La, Ce, Pr, Nd and Sm). For La7Pd3, electrical r esistivity rho shows a saturation tendency at high temperatures and th e superconducting transition at 6 K. For Ce7Pd3, rho does not show a K ondo character and has the antiferromagnetic transition at about 5 K a t under ambient pressure. For Pr7Pd3, rho has a remarkable concave dow nward curvature and the antiferromagnetic transition happens at 1.7 K under ambient pressure. For Nd7Pd3, the magnetic properties are sensit ive to pressure and the pressure-temperature magnetic phase diagram is constructed. For Sm7Pd3, at under ambient pressure the ferrimagnetic and the antiferromagnetic states appear below T-c = 167 K and T-t = 11 K, respectively. For Nd7Pd3 and Sm7Pd3, large positive volume-magneto strictions appear below magnetic transition temperature. (C) 1998 Else vier Science B.V. All rights reserved.