A ROTATIONAL VECTOR PREISACH MODEL FOR UNORIENTED MEDIA

Heretofore, vector Preisach models have consisted of angularly distributed scalar models. We postulate adding rotational capability to the binary response of the Preisach elements to obtain vector behavior using a single density function. A rotating field H divides the Preisach density function, which is obtained from scalar measurements, into regions associated with magnetization directions dependent on the applied field history. The magnetizations of elements with h*<∥H∥, where h* is the larger of the switching field magnitudes, follow exactly the direction of the rotating field. Those with h*>α∥H∥ (1<α<2 and is experimentally determined) are not oriented by H, but may be switched by the parallel component of H. Elements with intermediate values of h* rotate irreversibly at an angle which lags the field. The model has the same scalar properties in all directions and has performed well in simulating measurements made on a barium ferrite floppy disk with a vector vibrating sample magnetometer.