Effect of substitution of nickel on the magnetic properties of Sm2Co17

Publisher Website
Google Scholar
Abstract
Structural, metallographic and magnetic properties of Y2Co17−xNix and Sm2Co17−xNix have been established to ascertain the effect of nickel on the permanent magnet properties of Sm2Co17. The results indicate that the 2 : 17 compositions exist in the concentration limits 0<x2Co17−xNix and 0<x2Co17−xNix. Metallographic examination of these materials confirms the absence of secondary phases. Magnetic properties were examined in the temperature range 4.2–1200 K in external fields up to 21 kOe. The ordering temperatures of Sm2Co17−xNix and Y2Co17−xNix decrease with increasing concentration of nickel. Examination of saturation magnetization results indicates a smooth variation with the addition of nickel. The easy direction of magnetization at room temperature was established for the samples by examining the x‐ray diffraction patterns of aligned powders. The results show that the axial anisotropy exhibited by Sm2Co17 is retained with the substitution of nickel. For a few nickel‐rich compositions of Sm2Co17−xNix, thermomagnetic hysteresis effects were observed. The results are interpreted on the basis of a strong competition between the exchange field and the crystal field interaction. Calculations were performed to support this interpretation.