Wiggles in transition response of MIG ferrite heads

The cause of wiggles in the read-back signal of a series of MIG heads has been studied. A digitizing signal analyzer was used to analyze the read-back signals of the heads. These heads were then studied on a scanning magnetooptic photometer system by measuring the magnetic activity on the air-bearing surfaces. Defects having strong magnetic effects were observed in both the ferrite and the Sendust. It is shown that these defects are responsible for the wiggles in the read-back signal of these heads. It is believed that some defects in the Sendust are caused by variations of magnetic properties from grain to grain, and some are caused by diffusion of interface layer material taking place during the glass bonding process. The defects in ferrites are believed to be caused by inclusions