title: Switchable bi-stable multilayer magnetic probes for imaging of soft magnetic structures.
abstract: We present the use of custom-made multilayer (ML) magnetic probes in magnetic force microscopy (MFM) for imaging soft magnetic structures, i.e. nickel submicron disks of different dimensions. One of the main advantages of a custom-made ML probe is that it can be controllably switched between standard (parallel) and low moment (antiparallel) states. We demonstrate that the predicted vortex and stripe domain states in the disks are observed when using the ML probes both in the antiparallel and parallel states. However, while the phase contrast is significantly larger in the parallel state, the images are dominated by strong sample - probe interactions that obscure the image. By comparison of the stripe domain width observed by MFM with the ML probe and those expected from the Kittel model, we show that the resolution of the probe in the AP and P states is ∼30-40nm, i.e. of the order of the probe geometrical apex and thus approaching the limit of spatial resolution. The ML probes are further compared to the commercial standard and low moment ones, showing that the quality of images obtained with the ML probe is superior to both commercial probes.
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, UK; Royal Holloway University London, Egham, TW20 0EX, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Wren
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, UK; Royal Holloway University London, Egham, TW20 0EX, UK.
authors.forename: Robb
authors.initials: R
authors.lastname: Puttock
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, UK; Institute for Physics of Microstructures RAS, Nizhny Novgorod 603950, Russia.
authors.forename: Boris
authors.initials: B
authors.lastname: Gribkov
authors.affiliation: Institute for Physics of Microstructures RAS, Nizhny Novgorod 603950, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Vdovichev
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, UK. Electronic address: olga.kazakova@npl.co.uk.
authors.forename: Olga
authors.initials: O
authors.lastname: Kazakova
keywords: MFM; Magnetic probes; Scanning probe microscopy