Application of giant MR films to magnetic devices

In ultrahigh density magnetic recording, reproduced magnetoresistance (MR) heads utilizing giant magnetoresistance (GMR) multilayer material are expected to have a great advantage. Some requirements, such as adopting a noncoupled NiFe-Cu-Co-Cu multilayer for the GMR head, are discussed. The GMR sensors were fabricated by a lithography technique for optimal biasing behavior. The resistivities at zero field in a patterned Cr(50 angstrom)-[NiFe(20 angstrom)-Cu(35 angstrom)-Co(20 angstrom)-Cu(35 angstrom)] × 5 multilayer are increased with decreasing MR sensor height, owing to the magneto-static coupling between NiFe and Co layers. For the sample with an MR sensor height of 5 μm, a linear resistance change at around zero field is obtained without any bias field. The magnetization distributions for NiFe-Cu-Co-Cu GMR heads were calculated by the 2-dimensional integral element method. It was proved by the computer simulation that the yoke type GMR heads output level reaches 950 μV μm-1, according to the parameter optimization.