Coercivity enhancement of melt spun FePt ribbons by Au addition

Abstract

The effect of Au content on the magnetic properties and microstructure of melt spun (FePt)100−xAux (x=0–40) ribbons have been investigated. X-ray diffraction and thermal magnetic analysis results indicate that Au-rich phase coexists with ordered L10-FePt(Au) phase in ternary FePtAu ribbons after an isothermal annealing. Meanwhile, the Curie temperature of L10-FePt(Au) phase in annealed (FePt)100−xAux (x=0–40) ribbons is almost unchanged, revealing that higher volume fraction of Au addition does not modify the composition of the L10-FePt(Au) phase. All the Au containing ribbons exhibit a completely isolated L10-FePt(Au) granular structure, and the grain size is effectively decreased with the increase of Au content. As a result, the intrinsic coercivity (Hci) of the ribbons increases substantially from 2.1kOe for binary FePt to 19.5kOe for (FePt)60Au40.