Abstract
The measurements of Barkhausen noise, magnetic properties and hardness have been performed for heat-treated, thin plates of 45 Permalloy and the results are compared with cases of SK-4 steel and pure nickel. A uniform magnetic field was applied parallel to the surface of the plate to eliminate the ambiguity due to the demagnetization effect and a pickup coil was directly wound over the sample to observe Barkhausen noise only from the sample itself. The total Barkhausen noise energy is found to decrease with annealing which makes the material soft, showing a similar behavior to the case of pure nickel but a clear contrast to that of SK-4 steel.
