Magnetization dynamics in wire-shaped amorphous magnetic materials as probed by Barkhausen noise measurement

Abstract

Magnetic Barkhausen noise and hysteresis loops have been measured in the presence of various tensile stresses from three wire-shaped amorphous magnetic materials having different domain structures. Long duration large Barkhausen pulse indicates the presence of an inner core (IC) domain in positive magnetostrictive glass-coated Co83.2Mn7.6Si5.8B3.3 and Co58.59Fe4.41Ni10Si11B16 microwires where magnetization takes place by ∼180° rotation of domain magnetization. This long duration Barkhausen pulse is missing in the case of low negative magnetostrictive Co68.1Fe4.4Si12.5B15 wire indicating a negligible volume of IC domain in it. Short duration pulses observed in all three samples suggest the presence of a multi-domain outer shell where small angle rotation and domain wall displacement are responsible for the magnetization process. The shapes of the hysteresis loops support the Barkhausen noise studies.