Electrical & Computer Engineering Research Works

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Author: search.filters.author.Gomez, R. D.Subject: search.filters.subject.magnetization

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Now showing 1 - 4 of 4
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    Switching characteristics of submicron cobalt islands
    (American Institute of Physics, 1996-07-01) Gomez, R. D.; Shih, M. C.; New, R. M. H.; Pease, R. F. W.; White, R. L.
    The magnetic characteristics of 0.230.430.02 mm3 cobalt islands were investigated using magnetic force microscopy in the presence of an applied field. The islands were noninteracting and showed a wide variety of single and multidomain configurations. The distribution of magnetization directions supports earlier models which suggest that crystalline anisotropy plays a dominant role in establishing a dispersion of easy axis directions about the long axis of the particles. The magnetic evolution, involving rotation and switching of individual islands, was observed at various points along the microscopic magnetization curve. A magnetization curve of an ensemble of islands was derived from the images and compares remarkably well with macroscopic M–H measurements.
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    Domain wall motion in micron-sized Permalloy elements
    (American Institute of Physics, 1999-04-15) Gomez, R. D.; Luu, T. V.; Pak, O. A.; Mayergoyz, I. D.; Kirk, K. J.; Chapman, J. N.
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    Domain configurations of Permalloy elements
    (American Institute of Physics, 1999-04-15) Gomez, R. D.; Luu, T. V.; Pak, A. O.; Kirk, K. J.; Chapman, J. N.
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    Spin-current-induced magnetization reversal in magnetic nanowires with constrictions
    (American Institute of Physics, 2005-05-05) Florez, S. H.; Krafft, C.; Gomez, R. D.
    We have performed experiments on current-induced domain-wall motion sCIDWMd in the case of the domain walls sDWd trapped within the nanoscale constrictions in patterned NiFe structures. Direct observation of current-induced magnetization reversal was achieved and critical current densities jc were measured in the presence of easy-axis magnetic fields. The direction of CIDWM was found to be along the direction of the electron motion in absence of an applied magnetic field and in the direction of the field when in the presence of even relatively weak fields. Data for the field dependence of jc for both uniform and fast rising pulses suggest that the current, regardless of polarity, assists in the depinning of the DW. Only for the dc case does the data strongly reveal the influence of the electron pressure in promoting or hindering DW motion.