Study of the magnetoresistance of magnetic film modified by using ion beams

摘要

We have studied the magnetoresistance (MR) of locally modified Cu(20 nM)/AlO_x nm)/NiFe (20 nm)/AlO_x(l nm)/Cu(3 nm) on a Si substrate. The local modification was performed by irradiating Cu ion beams on a photoresist wire-covered film. After irradiation, the hysteresis loop shows step-like behavior at a specific ion dose, which is caused by the difference in the switching fields of the irradiated and unirradiated region of the film. Because of this, plateau-like behavior is observed in the transverse MR measurement of the film with 1 ×10~(16) ions/cm~2. A cross-sectional transmission electron microscopy image shows the irradiation induced intermixing of the magnetic layer with nonmagnetic layers.