A method for the calibration of magnetic force microscopy tips

A method is presented for the analysis of magnetic force microscopy (MFM) m easurements that allows the quantitative determination of the sample stray field. It is shown how measurements on an easily obtainable calibration sam ple can be used to calibrate the MFM measurement as a function of the wavel ength of the sample stray field at the tip apex. It is demonstrated that th e thus obtained MFM calibration can be used to determine the stray field di stribution of the tip. Furthermore, the effect of the tip on the MFM imagin g mechanism is analyzed by comparing it to some simple tip models. From the analysis, it is shown that the point-monopole and dipole models do not acc urately describe the MFM imaging mechanism. (C) 2000 American Institute of Physics. [S0021-8979(00)09113-1].