Switching characteristics and domain structures in amorphous toroidal cores

The switching characteristics of amorphous toroidal cores were investigated in the range of flux reversal time 10^-1∼ 10^-6sec and related to the observed behavior of magnetic domains. Samples used were amorphous-ribbon toroidal cores with multi-layer of Fe40Ni40P14B6(METGLAS 2826), Fe78Si10B12, Co74Si10B16, Fe5CO70Si15B10and Fe80P13C7. The switching time Ts for the flux reversal by constant-current pulse fields was measured for these cores as a function of effective applied field He (=applied field H - coercive force Hc). Domain patterns were observed for single-layer toroidal cores of Fe40Ni40P14B6(METGLAS 2826) by the Kerr effect. Both the number of domain walls and the average wall velocity were estimated from observed patterns. The non-linear dependences of Ts on He were explained in terms of the number of domain walls and the average wall velocity based on the observed domain behaviors.