A new model for the coercivity mechanism of Sm/sub 2/(Co,Fe,Cu,Zr)/sub 17/ magnets

Abstract

A two-dimensional model for the coercivity mechanism of Sm&!o,Fe,Cu,Zr)~, magnets is proposed. The high coercivities of fully heat-treated magnets (> 20 W c m ) result from pinning sites which are formed by the intersections of the Zr-rich platelet phase (Z-phase) and the Cu-rich SmCos (US) boundary phase. The pinning strength of this site is assumed to be a result of the large difference between the domain wall energies of the 115 phase and the Z-phase. The domain wall energies of almost single phase samples of the Zphase have been determined by magnetic measurements and by quantitative analysis of domain patterns. The small domain wall energy of the Z-phase of 4 -11 mJ/m2 supports the presented model.

Magnetization reversal process and intrinsic coercivity of sputtered Sm2Co17-based films

“…The cell boundary phase is believed to pin the domain walls during magnetization and demagnetization process. This is similar to the bulk SmCo 7 -based PMS in which the supersaturation of Cu and Zr is believed to play important roles in developing the cellular/lamellar microstructure and high coercivity [18][19][20]. As far as we know, the magnetization reversal process is sensitive to the microstructure of the Sm-Co-based PMS.…”

Studies of the domain structure of anisotropic sintered SmCo5 permanent magnets

“…[47,50,53,[59][60][61] and the values obtained are in the range 61-150 erg/cm 2 . (It was also estimated theoretically in Refs.…”

Nanocrystalline and Nanostructured High-Performance Permanent Magnets

“…It is obvious from this, that the lamellae are formed during the isothermal annealing at 800'C where they even develop their final chemical composition. Consequently, the evolution of the typical hard magnetic properties cannot be attributed to the lamellae as Katter [21] mistakenly presumed. In contrary, the chemical composition of the 1:5 cell boundary phase is mainly developed during the cooling procedure.…”