0000000000882515

AUTHOR

Laura J. Heyderman

showing 4 related works from this author

The effect of magnetic anisotropy on the spin configurations of patterned La(0.7)Sr(0.3)MnO3 elements.

2013

We study the effect of magnetocrystalline anisotropy on the magnetic configurations of La0.7Sr0.3MnO3 bar and triangle elements using photoemission electron microscopy imaging. The dominant remanent state is a low energy flux-closure state for both thin (15 nm) and thick (50 nm) elements. The magnetocrystalline anisotropy, which competes with the dipolar energy, causes a strong modification of the spin configuration in the thin elements, depending on the shape, size and orientation of the structures. We investigate the magnetic switching processes and observe in triangular shaped elements a displacement of the vortex core along the easy axis for an external magnetic field applied close to t…

Condensed matter physicsChemistryBar (music)02 engineering and technology021001 nanoscience & nanotechnologyCondensed Matter PhysicsMagnetocrystalline anisotropy01 natural sciencesVortexMagnetic fieldCondensed Matter::Materials ScienceDipolePhotoemission electron microscopyMagnetic anisotropy0103 physical sciencesGeneral Materials Science010306 general physics0210 nano-technologySpin (physics)Journal of physics. Condensed matter : an Institute of Physics journal
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Domain-wall induced large magnetoresistance effects at zero applied field in ballistic nanocontacts

2013

We determine magnetoresistance effects in stable and clean Permalloy nanocontacts of variable cross section, fabricated by UHV deposition and in situ electromigration. To ascertain the magnetoresistance (MR) effects originating from a magnetic domain wall, we measure the resistance values with and without such a wall at zero applied field. In the ballistic transport regime, the MR ratio reaches up to 50% and exhibits a previously unobserved sign change. Our results can be reproduced by recent atomistic calculations for different atomic configurations of the nanocontact, highlighting the importance of the detailed atomic arrangement for the MR effect. DOI: 10.1103/PhysRevLett.110.067203

PermalloyMaterials scienceCondensed Matter - Mesoscale and Nanoscale PhysicsMagnetic domainCondensed matter physicsMagnetoresistanceField (physics)530 PhysicsFOS: Physical sciencesGeneral Physics and Astronomy02 engineering and technology530 Physik021001 nanoscience & nanotechnology01 natural sciencesElectromigrationCross section (physics)Domain wall (magnetism)Ballistic conductionMesoscale and Nanoscale Physics (cond-mat.mes-hall)0103 physical sciences010306 general physics0210 nano-technologyPhysical Review Letters 110, 067203
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Optimal ferromagnetically-coated carbon nanotube tips for ultra-high resolution magnetic force microscopy

2013

Using single-walled carbon nanotubes homogeneously coated with ferromagnetic metal as ultra-high resolution magnetic force microscopy probes, we investigate the key image formation parameters and their dependence on coating thickness. The crucial step of introducing molecular beam epitaxy for deposition of the magnetic coating allows highly controlled fabrication of tips with small magnetic volume, while retaining high magnetic anisotropy and prolonged lifetime characteristics. Calculating the interaction between the tips and a magnetic sample, including hitherto neglected thermal noise effects, we show that optimal imaging is achieved for a finite, intermediate-thickness magnetic coating, …

Materials scienceFabrication530 PhysicsBioengineeringNanotechnologyddc:500.202 engineering and technologyCarbon nanotubeengineering.material01 natural scienceslaw.inventionCoatinglaw0103 physical sciencesGeneral Materials ScienceElectrical and Electronic Engineering010302 applied physicsbusiness.industryMechanical EngineeringResolution (electron density)General Chemistry530 Physik021001 nanoscience & nanotechnologyMagnetic anisotropyFerromagnetismMechanics of MaterialsengineeringOptoelectronicsMagnetic force microscope0210 nano-technologybusinessMolecular beam epitaxyNanotechnology
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Spin Wave Emission from Vortex Cores under Static Magnetic Bias Fields

2021

We studied the influence of a static in-plane magnetic field on the alternating-field-driven emission of nanoscale spin waves from magnetic vortex cores. Time-resolved scanning transmission X-ray microscopy was used to image spin waves in disk structures of synthetic ferrimagnets and single ferromagnetic layers. For both systems, it was found that an increasing magnetic bias field continuously displaces the wave-emitting vortex core from the center of the disk toward its edge without noticeably altering the spin-wave dispersion relation. In the case of the single-layer disk, an anisotropic lateral expansion of the core occurs at higher magnetic fields, which leads to a directional rather th…

magnetization dynamicsBioengineering02 engineering and technologyspin wavesVortex coresMagnetization dynamics; Magnonics; X-ray microscopy; Spin waves; Vortex coresvortex coresSpin waveDispersion relationGeneral Materials SciencemagnonicsX-ray microscopyAnisotropymagnetization dynamics ; magnonics ; X ray microscopy ; spin waves ; vortex coresPhysicsMagnonicsMagnetization dynamicsCondensed matter physicsMechanical EngineeringGeneral Chemistry021001 nanoscience & nanotechnologyCondensed Matter PhysicsMagnetic fieldVortexFerromagnetismMagnetization dynamicsMagnonics0210 nano-technologySpin waves
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