Low-temperature magnetic studies on various substituted rare earth (R)-transition metal (T) compounds RT 5

Abstract

Materials with partial substitution of the Co in SmCo 5 by the elements Ni, Pt, Cu, Ag, Al, In, Si, and Sn, were prepared and their structures identified. In a similar vein, Sm substitution by Zr in SmCo 5 was investigated as was Al substitution for Co in CeCo 5. Furthermore, results on Al substitution for Co in RCo 5 compounds, with R = Y, Gd, and Tb, are included. Stacking faults in the basal plane were observed in “as-melted” homogeneous compounds with Al and Si substitution for Co in SmCo 5. The magnetic properties of these materials, such as saturation moments and coercive forces, were investigated at 4.2 K. Al and Si substitution for Co in SmCo 5 results in outstanding coercive forces of the order of 30 – 50 kOe in powder and bulk materials. All other systems were disappointing in terms of magnetic hardness. The origin of outstanding magnetic hardness is discussed in terms of a model of the pinning of extremely energetic domain walls on obstacles of atomic dimension.