Filters

2013 - 20203

More filters

2019 - 20203
Reset filters

Settings

search.filters.applied.f.access: openAccess × Subject: Magnetic force microscopy ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Magnetic properties of GaAs-Fe3Si core-shell nanowires — A comparison of ensemble and single nanowire investigation
    (New York : American Institute of Physics, 2017) Hilse, Maria; Jenichen, Bernd; Herfort, Jens
    On the basis of semiconductor-ferromagnet GaAs-Fe3Si core-shell nanowires (Nws) we compare the facilities of magnetic Nw ensemble measurements by superconducting quantum interference device magnetometry versus investigations on single Nws by magnetic force microscopy and computational micromagnetic modeling. Where a careful analysis of ensemble measurements backed up by transmission electron microscopy gave no insights on the properties of the Nw shells, single Nw investigation turned out to be absolutely essential.
  • Thumbnail Image
    Item
    Round robin comparison on quantitative nanometer scale magnetic field measurements by magnetic force microscopy
    (Amsterdam : Elsevier B.V., 2020) Hu, X.; Dai, G.; Sievers, S.; Fernández-Scarioni, A.; Corte-León, H.; Puttock, R.; Barton, C.; Kazakova, O.; Ulvr, M.; Klapetek, P.; Havlíček, M.; Nečas, D.; Tang, Y.; Neu, V.; Schumacher, H.W.
    Magnetic force microscopy (MFM) can be considered as a standard tool for nano-scale investigation of magnetic domain structures by probing the local stray magnetic field landscape of the measured sample. However, this generally provides only qualitative data. To quantify the stray magnetic fields, the MFM system must be calibrated. To that end, a transfer function (TF) approach was proposed, that, unlike point probe models, fully considers the finite extent of the MFM tip. However, albeit being comprehensive, the TF approach is not yet well established, mainly due to the ambiguities concerning the input parameters and the measurement procedure. Additionally, the calibration process represents an ill-posed problem which requires a regularization that introduces further parameters. In this paper we propose a guideline for quantitative stray field measurements by standard MFM tools in ambient conditions. All steps of the measurement and calibration procedure are detailed, including reference sample and sample under test (SUT) measurements and the data analysis. The suitability of the reference sample used in the present work for calibrated measurements on a sub-micron scale is discussed. A specific regularization approach based on a Pseudo-Wiener Filter is applied and combined with criteria for the numerical determination of a unique regularization parameter. To demonstrate the robustness of such a defined approach, a round robin comparison of magnetic field measurements was conducted by four laboratories. The guideline, the reference sample and the results of the round robin are discussed.
  • Thumbnail Image
    Item
    Nanoscale magneto-structural coupling in as-deposited and freestanding single-crystalline Fe7Pd3 ferromagnetic shape memory alloy thin films
    (Abingdon : Taylor & Francis, 2013) Landgraf, A.; Jakob, A.M.; Ma, Y.; Mayr, S.G.
    Ferromagnetic shape memory alloys are characterized by strong magneto-mechanical coupling occurring at the atomic scale causing large magnetically inducible strains at the macroscopic level. Employing combined atomic and magnetic force microscopy studies at variable temperature, we systematically explore the relation between the magnetic domain pattern and the underlying structure for as-deposited and freestanding single-crystalline Fe7Pd3 thin films across the martensite-austenite transition. We find experimental evidence that magnetic domain appearance is strongly affected by the presence and absence of nanotwinning. While the martensite-austenite transition upon temperature variation of as-deposited films is clearly reflected in topography by the presence and absence of a characteristic surface corrugation pattern, the magnetic domain pattern is hardly affected. These findings are discussed considering the impact of significant thermal stresses arising in the austenite phase. Freestanding martensitic films reveal a hierarchical structure of micro- and nanotwinning. The associated domain organization appears more complex, since the dominance of magnetic energy contributors alters within this length scale regime.