Coercivity enhancement of melt spun FePt ribbons by Au addition

摘要

The effect of Au content on the magnetic properties and microstructure of melt spun (FePt)_(100-x)Au_x (x=0-40) ribbons have been investigated. X-ray diffraction and thermal magnetic analysis results indicate that Au-rich phase coexists with ordered L1_0-FePt(Au) phase in ternary FePtAu ribbons after an isothermal annealing. Meanwhile, the Curie temperature of L1_0-FePt(Au) phase in annealed (FePt)_(100-x)Au_x (x=0-40) ribbons is almost unchanged, revealing that higher volume fraction of Au addition does not modify the composition of the L1_0-FePt(Au) phase. All the Au containing ribbons exhibit a completely isolated L1_0-FePt(Au) granular structure, and the grain size is effectively decreased with the increase of Au content. As a result, the intrinsic coercivity (_iH_c) of the ribbons increases substantially from 2.1 kOe for binary FePt to 19.5 kOe for (FePt)_(60)Au_(40).