ON THE CHAOTIC OSCILLATIONS OF BLOCH WALLS AND THEIR CONTROL

In this paper elements of chaos theory are applied to the study of the dynamics of a model for a 180 degrees Bloch wall under the action of an alternating magnetic field. Only the case of soft ferromagnetic mat erials without nonferromagnetic inclusions is considered. The necessar y tools for the numerical investigation of the possible unstable oscil lations of such a system in the chaos domain of the control parameter are elaborated. This investigation implied the stabilisation of the os cillations by an adapted OGY parametric method, in which a control par ameter proportional to the field's amplitude was chosen. The study of the periodic orbits extracted from the chaotic attractor regards the d issipation on these orbits, which is compared to the power losses duri ng the uncontrolled chaotic oscillations and with those in the periodi city range of the control parameter. The conclusion is that periodic o rbits with power losses smaller than those of the other two types can be found. Copyright (C) 1997 Elsevier Science Ltd.