Magnetization switching of a magnetic wire with trilayer structure using giant magnetoresistance effect

The switching fields of magnetic wires with trilayer structure consisting o f NiFe/Cu/Co were investigated using giant magnetic resistance effect. The switching fields of both magnetic layers were observed to be inversely prop ortional to wire width (150-520 nm). We found that the magnetization of the NiFe layer switches under much lower applied field than in the case of sin gle layer structure by the assistance of the stray field from the magnetic charge of Co at the edge of the wire.. Attaching a pad at one end of the wi re causes drastic decrease of the switching field. We investigated pad shap e dependence of the switching field of the Co layer. For the sample with a square pad we measured the temperature dependence of the switching field be tween 5 and 300 K. The dependence at low temperatures between 5 and 50 K ca n be described by the model on thermally assisted magnetization reversal ov er a simple potential barrier. (C) 2000 American Institute of Physics. [S00 21-8979(00)03924-4].