Magnetocrystalline anisotropy of (PrDy)(FeCo)B sintered magnets

The magnetocrystalline anisotropy of uniaxial (PrDy)(FeCo)B rare-earth magnets is determined using the Akulov model and studied in the 2–300 K temperature. The (PrDy)(FeCo)B samples demonstrate the power dependence of anisotropy constant $K(T)$ on saturation magnetization $M_S(T)$ in the temperature range 2–300 K with exponents $m$ = 1.7–2.1, according to the empiric Callen–Callen rule. A deviation of power dependence $K(M_{S}^{m})$ is observed in the samples with the Gd impurity. Possible causes of the deviation from the Callen–Callen rule and variations of exponent m are discussed.