COERCIVITY AND MAGNETIC VISCOSITY OF NDDYFEB MECHANICALLY ALLOYED MAGNETS

We studied the temperature dependence of coercivity and magnetic visco sity in NdDyFeB mechanically alloyed magnets for temperatures between 25 and 500K. The results are discussed in terms of the so-called globa l model Of coercivity which provides information about the magnetic pr operties in the activation volume nu(alpha) where magnetization revers al is initiated. The anisotropy increase as well as the reduction of t he magnetization associated with the substitution of Dy for Nd are fac tors leading to the enhnacement of the coercive field, However, the co ntribution of microstructural features should also be considered.