Field-dependence of microscopic probes in magnetic force microscopy

We present a technique for characterizing the magnetic state of a magnetic force microscopy (MFM) probe as a function of uniform external magnetic field H. A local magnetic field is generated by micron-scale current carrying conductors and directly imaged by MFM. As H alters the magnetic state of the probe, changes in image contrast yield componentwise measures of the tip's net magnetic moment m, tip hysteresis loops and coercivities, and possible orientations (vertical vs lateral) of remanent states m, used for most MFM imaging. Results are presented for a variety of thin-film probes. (C) 1996 American Institute of Physics.