STRUCTURAL AND MAGNETIC-PROPERTIES OF R(3)(FE,T)(29) COMPOUNDS

We report the formation of several members of the recently discovered class of R(3)(Fe,T)(29) compounds and some of their intrinsic properti es. Focusing on materials with T=Ti and Cr, we have prepared R(3)(Fe,T i)(29) (R=Ce, Pr, Nd, Sm) and R(3)(Fe,Cr)(29) (R=Ce, Nd, Sm) compounds which all feature the novel monoclinic crystal structure first establ ished for Nd-3(Fe,Ti)(29). In each of the Ti- and Cr-containing groups the Ce member has the smallest magnetization, Curie temperature, and unit cell, suggesting that the Ce ion is tetravalent, or nearly so, in this family of materials. We observed no evidence of R(3)(Fe,Ti)(29) phase formation for R=Y, Gd, Dy, and Er. Our magnetization measurement s indicate that only Nd-3(Fe,Ti)(29) and Nd-3(Fe,Cr)(29) exhibit spin reorientations, at temperatures of 235 and 145 K, respectively.