DEPENDENCE OF BARKHAUSEN NOISE AND 2ND-HARMONICS ON MAGNETIZING FIELD ORIENTATION 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 peaks at the coercive force during a half cycle. The correspondence of BN peaks to those of second harmonics for phi = 0 degrees signifies the distribution of nucleation and annihilation of 180 degrees domains at the negative and positive knees of the B-H loop, respectively. As phi increases, for phi greater than or equal to 30 degrees three new peaks appear on the BN profile in addition;to the original two peaks associated with the nucleation and annihilation of 180 degrees and zig-zag domains. However, the three new peaks, two outside and one between the original peaks, are not found as corresponding peaks in the second harmonics. The hysteresis loss increases with phi due to the increased number of irreversible events during magnetization, while the marked decrease 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 dynamics.