GMR multilayers and head design for ultrahigh density magnetic recording

This paper describes materials development, device modeling, and initial test results for a novel GMR reproduce head for ultrahigh density recoding (similar to 10 Gbit/in(2)). It consists simply of a 20-bilayer GMR multilayer, self-stabilized by intrinsic antiferromagnetic interlayer coupling, and self-biased by sense current into a bipolar, field-gradient-sensing bias state. Analogous to a dual magnetoresistive (DMR) such a GMR-DMR head is capable of achieving very high linear resolution without shields. Tape-test results using evaporated NiFe/Cu and sputtered NiFeCo/Cu agree reasonably well with theoretical expectations. 1/f noise in these GMR multilayers will also be discussed.