| Popis: |
Multitrack integrated magnetic recording heads are very attractive for disc file memories. In spite of large interest for head per track application, integrated heads can be used on the moving arm. In this case, many heads are aligned on the same pad, reducing the access time. In order to increase the tracking accuracy, one servo head is on the same pad. The problem is to reduce significantly the perturbation produced by one data head at writing, upon the adjacent servo head (reading). Due to the very small separation between heads, shieldings are not efficient. In addition their implant is not simple and need machining. We have found a solution based on the compensation which can reduce crossfeed without shielding. Looking at two adjacent heads. We can distinguish three regions of interaction between heads : Region nb1 : Is defined as pole pieces interactions (no linear) Region nb2 : Is defined as coil interactions. (Linear) Region nb3 : Is defined as leads interactions (Linear) Generally, interactions 2 and 3 are large compared with the first one. In order to avoid interactions 2 and 3, we connect a compensating head (coiled in the opposite direction) just in front of and very near to servo head. To avoid interaction nb1, the pole pieces of compensating head are shorter than servo head, so as to be insensitive to medium fringing field. This compensating head can be deposited on separated substrate which is bonded as protective substrate on the one comprising data and servo heads. Another possibility is to deposit the servo head in two parts comprising servo and compensating heads. These methods will be discussed and results will show an important crossfeed reduction. We remark that these structures can be used only on thin film heads because of their flat geometry and could not be used for conventional heads. |
