Superparamagnetic magnetic force microscopy tips

We report on magnetic force microscopy (MFM) images of a thin-film magnetic recording head taken using batch micromachined silicon tips coated with nanocomposite Fe-60(SiO2)(40) and Fe-70(SiO2)(30) films. The small Fe grain size (<10 nm) and dilute Fe volume fraction (0.29-0.4) of these granular films produce tip coatings of low remanence and essentially zero coercivity, reduced by the superparamagnetic properties of these films. We have used these tips to obtain MFM images of the write field of the head with high spatial and magnetic-field resolution. In comparison to images taken using commercial Co85Cr15-coated tips, these MFM images show reduced tip memory effects and clearly delineate the gap field from the pole pieces. (C) 1996 American Institute of Physics.