Magnetization in a spin valve head mapped by an MFM tip

We have mapped the magnetization distribution in a spin valve head by monit oring its magneto-resistance delta R, while scanning the sample surface wit h an MFM tip. We find that conventional tips give enhanced response at two edges of the sensor. In comparison, mapping with horizontally magnetized ti ps shows no such artifacts. This is because conventional tips produce in-pl ane magnetic field components in all radial directions, thus the response d elta R does not simply correspond to local magnetization. In contrast, hori zontally magnetized tips produce fields along a single direction. Therefore , mapping of delta R renders the approximately single-domain magnetization in our spin valve films.