The novel use of a memory layer in a giant magnetoresistive position sensor design

A linear noncontact position sensor using Co/Cu giant magneto-resistance (G MR) multilayers as the sensing material and incorporating a magnetic memory layer has been designed and modeled. A magnetic head assembly acts as the position locator and the presence of a memory layer makes the throw length unlimited. A numerical model using charge sheets and finite elements has be en used to optimize the physical dimensions of the magnetic layers for diff erent magnetic materials and determine their spacing from the Co/Cu GMR sen sing material, The output from the sensor has been simulated as the head mo ves back and forth along the track, These results show that hysteresis in t he memory layer can be overcome by optimizing the head design, Using easily available materials, the modeling has shown that a device using second ant i-ferromagnetic (AF) peak Co/Cu is realizable, The model has also be used t o identify desirable material parameters for potential future engineered ma terials with the aim of utilizing high GMR first AF peak Co/Cu material in the sensor.