Competition of single-ion anisotropy of Sm and Dy ions during the spin-reorientation transition in (Nd1–x–ySmxDyy)(FeCo)B supermagnets

It has been found that an increase in the Sm concentration in the range x = 0.05–0.18 in (Nd1‒x‒ySmxDyy)(FeCo)B supermagnets leads to a shift in the spin-reorientation transition temperature to higher values, whereas a Dy addition results in a decrease in the transition temperature. Single-ion anisotropy of Sm and Dy ions has different symmetry, making contributions of opposite signs to the resulting magnetic anisotropy of the lattice. Therefore, the threshold temperature TS of the spin-reorientation transition, which is determined by the balance of magnetic anisotropies of sublattices, can be controlled using ions with different symmetries.