Magnetically soft phase in magnetization reversal processes of nanocompositeSm2Fe15Ga2Cx/α−Fepermanent magnetic materials

Abstract

The magnetic properties and magnetization reversal processes of nanocomposite ${\mathrm{Sm}}_{2}{\mathrm{Fe}}_{15}{\mathrm{Ga}}_{2}{\mathrm{C}}_{x}/\ensuremath{\alpha}\ensuremath{-}\mathrm{Fe}$ permanent magnet materials have been investigated. Remanence increases and intrinsic coercivity decreases drastically with increasing magnetically soft phase \ensuremath{\alpha}-Fe content. About 5 vol. % excess of \ensuremath{\alpha}-Fe results in a significant increase in maximum energy product from 5.6 MG Oe for single-phase nanocrystalline alloys to 8.2 MG Oe for two-phase nanocomposites. A further increase in \ensuremath{\alpha}-Fe content leads to a decrease of the maximum energy product owing to the rapid decrease of coercivity and the deterioration of the squareness of the hysteresis loop. The nucleation field for reversing the magnetically hard phase decreases monotonically with increasing \ensuremath{\alpha}-Fe content. Remanence enhancement, a high degree of reversibility, and high ratios of remanence coercivity to intrinsic coercivity are observed in two-phase nanocomposites.