Magnetic softening of bulk amorphous FeCrMoGaPCB rods by current annealing technique

Glassy rods of the Fe65.5Cr4Mo4Ga4P12C5B5.5 alloy were prepared by copper-mold casting technique under argon atmosphere with diameters of 1.5 and 1.8 ram. As-quenched and dc current annealed (CA) samples were examined by thermal analysis (DSC), X-ray diffraction (XRD), thermomagnetic and magnetic measurements. The appearance of a wide supercooled liquid region Delta T-x congruent to 60 K and high reduced glass transition temperature T-rg congruent to 0.57 indicated enhanced thermal stability against crystallization. Electrical resistivity (rho congruent to 210-220 mu Omega cm), coercive field (H congruent to 3-10 A/m), saturation polarization (J(s) congruent to 83 emu/g) and Curie temperature (T-C congruent to 448-460 K) were determined in the as-cast "XRD-amorphous" state. Maximum improvement in coercivity of about 30% was observed after applying a heating power per square area of Ps congruent to 4.4 and 3.7 W/cm(2) for 1.5 and 1.8 mm rods diameters, respectively. Coercivity behavior after CA treatments indicates the presence of a very small volume fraction of nanoscale crystalline inclusions that apparently hinder stress relief. (C) 2006 Elsevier B.V. All rights reserved.