The origin and interpretation of fine scale magnetic contrast in magnetic force microscopy: A study using single-crystal NdFeB and a range of magnetic force microscopy tips

We have used an oriented single crystal of Nd2Fe14B1 as a test sample to ex plore contrast and resolution as a function of magnetic force microscopy ti p coating, tip scan height, and sample history. We find that resolution is independent of tip type; that contrast is greater at low scan heights and f or higher moment tips; and that the fine length scale structure of order 25 nm can be resolved. We further show how the surface structure is a functio n of state (demagnetized or remanent), demonstrating the ability of well-ch aracterized studies to give high-resolution information on carefully prepar ed samples. (C) 1998 American Institute of Physics. [S0021-8979(98)16611-2] .