Reversible magnetization behavior in Sm2(Co,Fe,Cu,Zr)17

The magnetization of Sm-2(Co, Fe, Cu, Zr)(17) is determined by the motion of domain boundary walls that are subject to pinning. Measurements have been made of the relationship between the reversible magnetization M-rev and the irreversible magnetization M-irr components in Sm-2(Co, Fe, Cu, Zr)(17). The results are consistent with a model in which rapid nucleation of domain walls occurs at the beginning of magnetization reversal followed by gradual unpinning of the domain walls. For Sm-2(Co, Fe, Cu, Zr)(17) the parameter eta, defined as eta=(dM(rev)/dM(irr))(H) is similar in form to previously observed variations of eta in sintered NdFeB but very different from eta variations due to Stoner-Wohlfarth coherent rotation of magnetization vectors. (C) 1999 American Institute of Physics. [S0021-8979(99)44608-0].