Effect of neutron irradiation on magnetic properties in the low alloy Ni-Mo steel SA508-3

The B-H hysteresis loop and Barkhausen noise have been measured in the neutron irradiated SA508 steel of 45 $\mu$ m thickness. The coercive force of B-H loop showed a slow change up to a neutron dose of 10${}^{14}$ n/cm${}^2$ and increased by 15.4% for a 10${}^{16}$ n/cm${}^2$ dose sample compared with that of the unirradiated one, related to the domain wall motion hindered by the increased defects. However, the amplitude of Barkhausen noise reflecting the wall motion decreased slowly up to 10${}^{14}$ n/cm${}^2$ irradiation, followed by a rapid decrease of 37.5% at 10${}^{16}$ n/cm${}^2$ .