Structural and magnetic investigations of some new boron containing rare earth intermetallic compounds

Abstract

By alloying boron with RPd₃ (R=rare earth) compounds, new ternary alloys of the formula RPd₃B_x (0≤x≤1) have been prepared. The parent RPd₃ compounds crystallise in the cubic AuCu₃ type structure. The addition of boron does not change the structure but results in an expansion of the lattice. Therefore, it is likely that the small boron atoms occupy the vacant body centred position in AuCu₃ type structure. It is also observed that compounds of the composition RRh₃B can be formed in the cubic structure for all rare earths R though the parent RRh₃ compounds exist only for R=Ce (AuCu₃ type) and La, Sm, Nd and Gd (all hexagonal CeNi₃ type). This points out the role of boron in stabilising new crystallographic phases. The results of susceptibility measurements on some of the RPd₃B and RRh₃B compounds are presented. In particular, it is noted that while GdPd₃ orders antiferromagnetically with T_N=6 K, GdPd₃B does not order magnetically down to 4.2 K.