ANALYSIS OF THE COERCIVE FIELD IN SM2FE17NX METAL-BONDED MATERIAL

In the present paper the nucleation as well as the pinning fields in S M2Fe17Nx Sn-bonded material are analysed based on the well established micromagnetic theory. The microstructural parameters derived from the measured temperature dependence of the coercive field indicate that t he coercive field in Sm2Fe17Nx Sn-bonded material is dominated by the nucleation field occurring in the inhomogeneous area near the grain su rface. The magnetic phase transition at the Curie temperature from the ferromagnetic to the paramagnetic state of the magnetically soft phas e Sm2Fe17 existing in SM2Fe17Nx magnets leads to a decrease of the eff ective demagnetization factor. Furthermore the temperature dependence of the domain wall energy gamma, the average exchange constant A, the domain wall width delta(B), as well as the critical diameter of a sing le domain particle D(c) for SM2Fe17Nx are also derived in the temperat ure range from 200 to 580 K.