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

By alloying boron with RPd<SUB>3</SUB> (R=rare earth) compounds, new ternary alloys of the formula RPd<SUB>3</SUB>B<SUB>x</SUB> (0&#8804;x&#8804;1) have been prepared. The parent RPd<SUB>3</SUB> compounds crystallise in the cubic AuCu<SUB>3</SUB> 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 AuCu<SUB>3</SUB> type structure. It is also observed that compounds of the composition RRh<SUB>3</SUB>B can be formed in the cubic structure for all rare earths R though the parent RRh<SUB>3</SUB> compounds exist only for R=Ce (AuCu<SUB>3</SUB> type) and La, Sm, Nd and Gd (all hexagonal CeNi<SUB>3</SUB> type). This points out the role of boron in stabilising new crystallographic phases. The results of susceptibility measurements on some of the RPd<SUB>3</SUB>B and RRh<SUB>3</SUB>B compounds are presented. In particular, it is noted that while GdPd<SUB>3</SUB> orders antiferromagnetically with T<SUB>N</SUB>=6 K, GdPd<SUB>3</SUB>B does not order magnetically down to 4.2 K