Computer simulation of Lorentz electron micrographs of thin magnetic particles

Haug, Tobias; Otto, Stephan; Schneider, M.; Zweck, Josef

doi:10.1016/s0304-3991(03)00008-1

Cited by 13 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The combination of these two complementary methods was already successfully applied in the case of Nickel rhombs [9]. The Lorentz microscopy is supported by numeric image simulations [10].…”

Section: Introductionmentioning

confidence: 93%

Magnetization configurations and hysteresis loops of small permalloy ellipses

Schneider

Liszkowski

Rahm

et al. 2003

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

We investigated systematically the easy axis magnetization reversal of 20 nm thick permalloy ellipses with a fixed major axis of 1.47 µm and minor axes of 0.22–1.47 µm. Lorentz transmission electron microscopy was used to image the micromagnetic configurations during magnetization reversal. Hysteresis loops of single ellipses were recorded by means of micro-Hall magnetometry and could be traced back to certain reversal mechanisms observed by Lorentz microscopy. In most cases, the magnetization reversal is initiated by the evolution of a magnetization buckling, followed by the formation of a single, a double, or a trapped vortex configuration. For ellipses with high aspect ratio (length-to-width ratio), the magnetization switches in the reversed magnetic field without creation of a stable vortex configuration. Our experiments show that the characteristic field values for vortex creation, single vortex annihilation, and switching strongly depend on the shape anisotropy of the elements.

show abstract

Section: Introductionmentioning

confidence: 93%

Magnetization configurations and hysteresis loops of small permalloy ellipses

Schneider

Liszkowski

Rahm

et al. 2003

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…24 Twodimensional magnetization patterns are input for the image simulations. The Fresnel image simulations were carried out using the software package GENIUS.…”

Section: Lorentz Microscopy and Image Simulationmentioning

confidence: 99%

Stability of magnetic vortices in flat submicron permalloy cylinders

Schneider

Hoffmann

Otto

et al. 2002

Journal of Applied Physics

View full text Add to dashboard Cite

Lattice symmetry and magnetization reversal in micron-size antidot arrays in Permalloy filmWe have investigated the magnetic properties of flat permalloy cylinders by Lorentz transmission electron microscopy and micromagnetic simulations. The magnetization patterns during in situ magnetizing experiments have been imaged and they revealed that the magnetization reversal of the cylindrically shaped dots investigated is determined by the formation and annihilation of magnetic vortices. Furthermore, the experiments and micromagnetic simulations showed a dependence of the vortex annihilation field not only on the aspect ratio but also on the absolute thickness of the cylinders. The diameter of the cylindrical dots was varied between 150 and 1000 nm, and the thicknesses were 3, 5.5, 8.3, 15, and 20 nm, respectively. The formation of inhomogeneous magnetization patterns prior to vortex evolution was observed and by a comparison of the experimental to simulated Fresnel images these patterns can be identified as S-and C-like states.

show abstract

“…Here we describe how MALTS can convert the outputted .omf file from OOMMF or MuMax into a corresponding LTEM image. Similar software called GENIUS was presented by Haug et al [17] in 2003, but we were unable to obtain it. We provide our MALTS both as precompiled executables and as open source code, allowing users to expand and improve on the functionality.…”

Section: Introductionmentioning

confidence: 97%

“…However for more complex magnetic structures, the LTEM contrast is not so intuitive or easy to understand making simulation important. Several different groups [5]- [12], [16], [17] have published simulations of LTEM contrast, obtained using code based on similar equations, but not generally available, rendering comparison between different simulations challenging. For example Qi et al [5], [6] use a simple MATLAB program which works on structures uniformly magnetised in the x-direction, while McVitie and Cushley [7] have a more complex simulator capable of studying multiple domain structures.…”

Section: Introductionmentioning

confidence: 99%

MALTS: A Tool to Simulate Lorentz Transmission Electron Microscopy From Micromagnetic Simulations

et al. 2013

View full text Add to dashboard Cite

Here we describe the development of the MALTS software which is a generalized tool that simulates Lorentz Transmission Electron Microscopy (LTEM) contrast of magnetic nanostructures. Complex magnetic nanostructures typically have multiple stable domain structures. MALTS works in conjunction with the open access micromagnetic software Object Oriented Micromagnetic Framework or MuMax. Magnetically stable trial magnetization states of the object of interest are input into MALTS and simulated LTEM images are output. MALTS computes the magnetic and electric phases accrued by the transmitted electrons via the Aharonov-Bohm expressions.Transfer and envelope functions are used to simulate the progression of the electron wave through the microscope lenses. The final contrast image due to these effects is determined by Fourier Optics. Similar approaches have been used previously for simulations of specific cases of LTEM contrast. The novelty here is the integration with micromagnetic codes via a simple user interface enabling the computation of the contrast from any structure. The output from MALTS is in good agreement with both experimental data and published LTEM simulations. A widely-available generalized code for the analysis of Lorentz contrast is a much needed step towards the use of LTEM as a standardized laboratory technique.

show abstract

Computer simulation of Lorentz electron micrographs of thin magnetic particles

Cited by 13 publications

References 17 publications

Magnetization configurations and hysteresis loops of small permalloy ellipses

Magnetization configurations and hysteresis loops of small permalloy ellipses

Stability of magnetic vortices in flat submicron permalloy cylinders

MALTS: A Tool to Simulate Lorentz Transmission Electron Microscopy From Micromagnetic Simulations

Contact Info

Product

Resources

About