Annealing and neutron irradiation effects on the magnetic properties of Fe73.5Cu1Nb3Si13.5B9

The annealing and neutron irradiation effects on the magnetic properties of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy were investigated. The sample was exposed by fast (4.85×1016 nf cm2) and thermal (8.01×1018 nth cm2) neutrons at the temperature of 473 K. The complex magnetic permeability spectra changed with the ac field amplitude, reflecting the contribution of wall motion and rotational magnetization in as-quenched sample. The neutron irradiation sample showed the drastic decrease of permeability from wall motion but the increase of permeability from rotational magnetization, compared to those in as-quenched and annealed samples at 473 K. As a whole, dc permeability in neutron irradiated sample was larger than that of the as-quenched sample. The measurement of hysteresis loop showed the increase of magnetic softness after the neutron irradiation, but saturation magnetization was insensitive to the neutron irradiation. These results indicated that magnetic softness was improved by the enhancement of rotational magnetization