Phase formation and magnetic properties of SmCo5+x alloys with the TbCu7-type structure

Abstract The metastable TbCu 7 -type structure has been formed over a range of compositions ranging from SmCo 5.67 to SmCo 8 . The stabilization was attributed to the addition of Nb combined with rapid solidification processing. As a result, the concentration of transition metal dumbbells varied, while the placement in the structure remained random. The coercivity varied linearly with composition and was highest in Sm-rich compositions (17.5 kOe ) and decreased to ∼3 kOe as Sm content decreased. The variation in coercivity was attributed to a decrease in magnetocrystalline anisotropy, with estimations predicting that the anisotropy varies linearly with composition between values reported for the compounds SmCo 5 and Sm 2 Co 17 .