The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Peter Fischer - One of the best experts on this subject based on the ideXlab platform.
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real space observation of Dipolar Interaction in arrays of fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism.
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Real space observation of Dipolar Interaction in arrays of Fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Dong-hyun Kim, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism. (C) 2006 American Institute of Physics.
A O Adeyeye - One of the best experts on this subject based on the ideXlab platform.
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Direct detection of neighboring stray field Interaction on a single nanodisk using micro-focused Brillouin Light Scattering spectroscopy
2015 IEEE International Magnetics Conference (INTERMAG), 2015Co-Authors: G Shimon, A O AdeyeyeAbstract:Studying the effect of Dipolar Interaction between closely-packed nanodisks has become increasingly important in many applications such as high density information storage, magnonics crystals and spin torque oscillators. So far, these studies were focused on the collective magnetic behavior from an array rather than from a single disk under the influence of neighboring Dipolar field. Recently, Keatley et al used a time-resolved scanning Kerr microscopy to isolate the dynamic Dipolar Interaction between a pair of nominally-shaped disks. However, a detailed scrutiny of phase-resolved Kerr ellipticity is required to determine, with limited accuracy, the dynamic Dipolar coupling strength versus edge-to-edge spacing/diameter (s/d) ratio. In this work, we use a micro-focused Brillouin Light Scattering (μ-BLS) setup to systematically investigate the effect of increasing neighboring Dipolar field on the dynamic behavior of a single nanodisk. Using pairs of identical disks with varying s, a direct detection of increasing neighboring Dipolar field on a single disk is systematically performed. The influence of neighboring Dipolar field in modifying the dynamic behavior of the resonance mode is evident in the measured spectra and the 2D mode profiles. In addition, by changing the relative orientation between the inter-disk coupling direction and the applied magnetic field (Happ) to be either parallel or perpendicular, different modes of Dipolar Interaction can be further distinguished.
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direct detection of static Dipolar Interaction on a single nanodisk using microfocused brillouin light scattering spectroscopy
Advanced electronic materials, 2015Co-Authors: G Shimon, A O AdeyeyeAbstract:Direct probing of how the static Dipolar field from neighboring disk affects the dynamic behavior of a single disk using microfocused Brillouin light scattering spectroscopy is presented. Using pairs of identical Ni80Fe20 disks (diameter d = 500 nm) and by varying the inter-disk spacing (s) in the range from 50 to 500 nm, a marked spectral and spatial shift in the resonant mode with increasing Dipolar Interaction (by reducing s) is demonstrated. When the disks are in a single domain state (at high magnetic field), the Dipolar Interaction is highly anisotropic depending on the relative orientation between the inter-disk coupling direction and the applied field. The effect of Dipolar Interaction on the resonant frequency greatly diminishes when the disks are in a vortex state (at low field). Micromagnetic simulations and analytical calculations are in good agreement with our experimental results. The results and methodology presented in this work are useful in further development of high density magnetic recording media, functional microwave signal processing, and logic devices.
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Effect of Dipolar Interaction on the magnetization state of chains of rectangular particles located either head-to-tail or side-by-side
Journal of Nanoparticle Research, 2011Co-Authors: D. Bisero, A O Adeyeye, P. Cremon, M. Madami, M. Sepioni, S. Tacchi, G. Gubbiotti, G. Carlotti, N. Singh, S. GoolaupAbstract:Magnetostatic coupling in arrays of closely spaced magnetic elements is becoming an important issue in the path to the fabrication of spintronic devices. Dense chains of rounded-corners rectangular particles (dots) of lateral size 1025 × 450 nm^2, with interdot spacing variable in the range between 55 and 700 nm, have been patterned by deep UV lithography, followed by the lift-off of two permalloy films of thickness 20 and 40 nm. Magneto-optical Kerr effect (MOKE) and magnetic force microscopy (MFM) experiments, together with micromagnetic simulations, were performed to study the dependence of the magnetization configuration on the Dipolar coupling. Both MOKE measurements and MFM images clearly show that, at remanence, the magnetic state of isolated particles of thickness 20 nm takes the form of a distorted single domain (C-state or S-State configurations). Instead, when the particle thickness is double (40 nm), closure states characterized by one, two or three vortices occur at remanence. However, when the 40 nm thick dots are placed in chains along the easy axis (head to tail), as the separation is progressively reduced, the single domain state is stabilized at remanence. On the other hand, when the 40 nm thick particles are placed side by side in chains the effect of Dipolar Interactions is to favour the nucleation of vortex states. For small inter-element separation, there is only one vortex per particle and it has the same chirality in adjacent particles, due to the Dipolar Interaction. Different from this, for the 20 nm thick samples and sub-100 nm separation, adjacent particles are single-domain but with antiparallel magnetization in neighbour elements, like in an artificial antiferromagnet.
Markus Bolte - One of the best experts on this subject based on the ideXlab platform.
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real space observation of Dipolar Interaction in arrays of fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism.
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Real space observation of Dipolar Interaction in arrays of Fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Dong-hyun Kim, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism. (C) 2006 American Institute of Physics.
Gil Navon - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Dipolar Interaction of23Na in Solution by Triple-Quantum Relaxation Time Measurements
Journal of Magnetic Resonance, 2002Co-Authors: Uzi Eliav, Gil NavonAbstract:Abstract The measurement of the Dipolar Interaction of 23 Na with hydrogen nuclei in glycerol solution is reported. The method, applied previously to 7 Li (U. Eliav and G. Navon, J. Magn. Reson. A 123, 32 (1996)), is based on the measurement of the triple-quantum relaxation time of 23 Na. Several models of motion are discussed. The analysis of the results yielded 1.9 MHz and 12.5 kHz for the quadrupolar and the 23 Na– 1 H Dipolar Interaction, respectively. It is shown that under the conditions of long correlation times the triple-quantum relaxation time can be sensitive to Dipolar Interactions smaller than the quadrupolar Interaction by as much as a factor of 5000. This indicates the possibility of measuring interatomic distances for nuclei with sizable quadrupolar moments.
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measurement of Dipolar Interaction of quadrupolar nuclei in solution using multiple quantum nmr spectroscopy
Journal of Magnetic Resonance Series A, 1996Co-Authors: Uzi Eliav, Gil NavonAbstract:Abstract Relaxation resulting from the modulation of Dipolar Interaction is commonly used for estimating distances in molecules in solutions. However, for most nuclei with spin I > 1 2 the single-quantum-transition relaxation by Dipolar Interaction is masked by quadrupolar relaxation. In the present study, it is shown that even in systems where single-quantum relaxation times are dominated by quadrupolar Interaction, Dipolar relaxation can be measured by following the − m [formula] m transitions. This is demonstrated for 7 Li in the complex [Li–Kryptofix 211] + X − (X = Cl, Br) dissolved in glycerol at temperatures for which slow motion prevails and no 1 H– 7 Li NOE can be observed. The relaxation times that are most important for the assessment of the Dipolar Interaction of 7 Li are − 1 2 [formula] 1 2 and −[formula][formula][formula]and they are measured by multiple-quantum-filtration techniques. For estimating the quadrupolar Interaction, the relaxation times of the populations and those of the transitions ± 1 2 [formula]±[formula]were measured. The longitudinal and transverse relaxation times of 6 Li as well as the 1 H– 6 Li NOE were also measured and, together with the 7 Li measurements, were used to obtain the strengths of Dipolar ( D ) and quadrupolar (χ) Interactions. The experimental data were analyzed using several models to describe the motion. The model that gave the best fit and resulted in parameters that were physically meaningful encompassed a whole-body isotropic motion as well as internal anisotropic motion. For this particular model, the following values for the quadrupolar and the Dipolar Interactions strength were obtained: D ( 7 Li)/2π = 6.8 kHz, χ( 7 Li)/2π = 85 kHz and D ( 6 Li)/2π = 1.4 kHz, χ( 6 Li)/2π = 2.6 kHz. From the value of D , an estimate of the average lithium–proton distance was calculated to be 3.3 A, which is in fair agreement with crystallographic studies. The sizes of the quadrupolar and Dipolar Interactions were independently confirmed by the 7 Li NMR powder spectra of the complexes that were used for the solution studies.
René Eiselt - One of the best experts on this subject based on the ideXlab platform.
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real space observation of Dipolar Interaction in arrays of fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism.
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Real space observation of Dipolar Interaction in arrays of Fe microelements
Journal of Applied Physics, 2006Co-Authors: Markus Bolte, René Eiselt, Dong-hyun Kim, Guido Meier, Peter FischerAbstract:Square lattice arrays of thin microelements of Fe are investigated by magnetic transmission x-ray microscopy. The influence of dipole Interaction is analyzed by varying the interelement distance. For comparison isolated elements are prepared on the same sample. The magnetostatic field caused by interelement Interaction leads to a substantial stabilization of the elements in the center of the array comparable to the magnetization process previously found by numerical solution of the Landau-Lifshitz equation for magnetic dot arrays. Micromagnetic simulations show that for high field strengths the Dipolar Interaction is collinear with the external field while in the low-field regime the strayfields have significant perpendicular components leading to a complex reversal mechanism. (C) 2006 American Institute of Physics.