Variation of magnetoresistive sensitivity maps of patterned giant magnetoresistance sensors

A scanning probe microscope which combines probe contacts for the supply of current with a magnetic force microscope (MFM) for fully automated imaging of electrically active, patterned sensor-like devices across a wafer was d eveloped. This was used for magnetoresistive sensitivity mapping (MSM) of g iant magnetoresistive sensors with different stabilization schemes. Multipl e measurements of sensors showed that the MSM images were very repeatable. The complex image patterns varied significantly from sensor to sensor acros s a wafer. With MFM tips magnetized perpendicular to the ferromagnetic film s in the sensor, MSM signals at the top and bottom of the sensor were signi ficantly more intense than signals at the sensor interior. Results from mic romagnetic calculations were found to be consistent with the experimental o bservations. (C) 2001 American Institute of Physics.