AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Thursday Sessions
       Session MI+NS-ThA

Paper MI+NS-ThA2
Modified Tips for High Resolution In-plane Magnetic Force Microscopy

Thursday, October 28, 1999, 2:20 pm, Room 618/619

Session: Magnetic Imaging
Presenter: L. Folks, IBM Almaden Research Center
Authors: L. Folks, IBM Almaden Research Center
J.N. Chapman, University of Glasgow, UK
M.E. Best, IBM Almaden Research Center
P.M. Rice, IBM Almaden Research Center
B.D. Terris, IBM Almaden Research center
D. Weller, IBM Almaden Research Center
Correspondent: Click to Email
Commercial batch-fabricated coated MFM tips have been modified to allow high resolution imaging of the in-plane components of stray field above a sample. A hole of diameter ~ 20nm was milled through the magnetic coating layer to the underlying silicon at the apex of each tip with a focussed gallium ion beam. The tips were then magnetized in the direction parallel to the sample plane. The hole at the apex forms a small pole gap and it is the interaction of the stray field from this gap with the sample stray field which produces the MFM signal. Accordingly, the resolution achievable is determined by the diameter of the hole milled at the apex. Note that such a controlled modification of the magnetic tip coating was suggested by Hill.@footnote 1@ High and low density data tracks, with transition spacings ranging from 1 micrometer to 50 nanometers, written in longitudinal granular recording media have been used to demonstrate the utility of the tips. By comparison of experimental results with simple theoretical models it is shown that the tips are strongly sensitive to the in-plane components of stray field. Furthermore, the modified tips exhibit better resolution than the unmodified tips, as may be seen from a side-by-side comparison of data collected from high density written transitions. The modified tips offer an inexpensive route to high resolution imaging of stray fields associated with in-plane domain structures. Hence they are of particular value for high density magnetic recording media investigations since the in-plane component of stray field is closely related to the signal detected by the recording head. @FootnoteText@ @footnote 1@ E. W. Hill, IEEE Trans. Magn. 31, 3355 (1995).