DEPENDENCE OF BARKHAUSEN NOISE AND 2ND-HARMONICS ON MAGNETIZING FIELDORIENTATION IN 3-PERCENT SILICON-IRON

The profile of Barkhausen noise (BN) and second harmonics are measured during B-H hysteresis loops as a function of the angle, phi, between the H-field applied and the [001] axis in (110)[001] grain oriented 3% silicon iron. The BN profile for phi = 0 degrees splits into two peak s at the coercive force during a half cycle. The correspondence of BN peaks to those of second harmonics for phi = 0 degrees signifies the d istribution of nucleation and annihilation of 180 degrees domains at t he negative and positive knees of the B-H loop, respectively. As phi i ncreases, for phi greater than or equal to 30 degrees three new peaks appear on the BN profile in addition;to the original two peaks associa ted with the nucleation and annihilation of 180 degrees and zig-zag do mains. However, the three new peaks, two outside and one between the o riginal peaks, are not found as corresponding peaks in the second harm onics. The hysteresis loss increases with phi due to the increased num ber of irreversible events during magnetization, while the marked decr ease in BN energy at phi = 30 degrees is attributed to the small pulse height of non-180 degrees walls involved in the zig-zag domain dynami cs.