Domain patterns and high-frequency magnetic properties of amorphous metal ribbons

Abstract

Domain patterns and hysteresis curves were studied on field annealed amorphous ribbons of Co70.3Fe4.7Si15B10. The domain structure was observed with the longitudinal Kerr effect. Hysteresis curves and permeabilities were measured at frequencies up to 10 MHz and in fields up to 2 kA/m in the length direction of the ribbon. The frequency dependence of the permeability and the hysteresis curves in the MHz range, measured after annealing in a field perpendicular to the ribbon axis in the plane of the ribbon, can be fully explained by assuming that only rotation contributes to the magnetization and that losses are due to eddy currents. Specimens annealed in a field perpendicular to the ribbon plane behave similarly. After annealing in a field parallel to the ribbon axis, however, only wall displacements occur, leading in the MHz range to a low permeability and large additional contributions to the losses.