One- and two-dimensional magnetization processes in amorphous alloys

The hysteresis loop and loss properties of near-zero-magnetostrictive amorphous ribbons have been investigated as a function of the induced macroscopic magnetic anisotropy K-u from dc to 10 kHz. It is found that, following the evolution of K-u, imposed by means of sequential field annealings along the longitudinal (LD) and transverse (TD) directions, the hysteresis loop shape and area and the frequency dependence of energy losses suffer dramatic changes, dictated by the value of K, and the local distributed anisotropies K. On passing from longitudinal to transverse macroscopic easy axis, coherent spin rotations come into play and, in association with the domain wall displacements, eventually provide a net magnetization reversal along both LD and TD. The hysteresis loss component W-h correspondingly increases and the energy loss at high frequencies decreases. It is concluded that: (1) optimal quasi-static magnetic behavior requires relatively high and positive K-u values (>50-100 J/m(3)), with longitudinal plane rigid walls and (2) the best high frequency properties are attained for K-u similar to 0, where flexible walls and complex domain patterns are created. (C) 1997 American Institute of Physics.