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Displaying 26 - 50 of 69

Spin Waves Across Three-Dimensional, Close-Packed Nanoparticles

December 21, 2018
Author(s)
Kathryn Krycka, James Jennings Rhyne, Samuel D Oberdick, Ahmed M. Abdelgawad, Julie A. Borchers, Yumi Ijiri, Sara A. Majetich, Jeffrey W. Lynn
Inelastic neutron scattering is utilized to measure the spin waves, or magnons, which arise from inter-particle coupling between 8.4 nm ferrite nanoparticles that are self-assembled into a close-packed lattice, yet physically separated by oleic acid

Phase-Sensitive Small-Angle Neutron Scattering Experiment

September 19, 2018
Author(s)
Erik Brok, Kathryn L. Krycka, Erika C. Vreeland, Andrew Gomez, Dale L. Huber, Charles Majkrzak
Small angle neutron scattering is a useful technique for determining the structure of biomolecules in solution. However, because of the well-known problem that the phase of the scattered wave is lost in scattering experiments, unambiguous structural

Spin Canting Across Core/Shell Fe 3 O 4 /Mn x Fe 3-x O 4 Nanoparticles

February 21, 2018
Author(s)
Samuel D. Oberdick, Ahmed Abdelgawad, Carlos Moya, Samaneh Mesbahi-Vasey, Demie Kepaptsoglou, Vlado K. Lazarov, Richard F. L. Evans, Daniel Meilak, Elizabeth Skoropata, Johan van Lierop, Ian Hunt-Isaak, Hillary Pan, Yumi Ijiri, Kathryn L. Krycka, Julie Borchers, Sara A. Majetich
Core/shell Fe 3dO 4/Mn xFe 3-xO 4 nanoparticles were synthesized in a single reaction using molecular precursors with different thermal stability. Scanning transmission electron microscopy combined with electron energy loss spectroscopy confirms the core

Self-assembled Layering of Magnetic Nanoparticles in a Ferrofluid onSilicon Surfaces

January 4, 2018
Author(s)
Katharina Theis-Brohl, Erika C. Vreeland, Andrew Gomez, Dale L. Huber, Apurve Saini, Max Wolff, Brian B. Maranville, Erik Brok, Kathryn L. Krycka, Joseph Dura, Julie Borchers
This article describes the 3D self-assembly of monodisperse colloidal magnetite nanoparticles from a dilute water-based ferrofluid onto a silicon surface and the dependence of the resultant magnetic structure with applied field. The nanoparticles assemble

Complex Three-Dimensional Magnetic Ordering in Segmented Nanowire Arrays

July 12, 2017
Author(s)
Alexander J Grutter, Kathryn Krycka, Elena V. Tartakovskaya, Julie A. Borchers, K. Sai Madhukar Reddy, Eduardo Ortega, Arturo Ponce, Bethanie J. H. Stadler
The first comprehensive three-dimensional picture of magnetic ordering in high-density arrays of segmented FeGa/Cu nanowires is experimentally realized through the application of Polaris small angle neutron scattering. The competing energetics of dipolar

Spin-Analyzed SANS for Soft Matter Applications

June 20, 2017
Author(s)
WangChun Chen, John Barker, Ronald L. Jones, Kathryn Krycka, Shannon Watson, Cedric Victor Lucien Gagnon, T. Perevozchivoka, Paul Butler, Thomas R. Gentile
The small angle neutron scattering (SANS) of nearly Q-independent nuclear spin-incoherent scattering from hydrogen present in most soft matter and biology samples may raise an issue in structure determination in certain soft matter applications. This is

Internal Magnetic Structure of Nanoparticles Dominates Time-Dependent Relaxation Processes in a Magnetic Field

June 2, 2015
Author(s)
Cindi L. Dennis, Kathryn L. Krycka, Julie Borchers, Ryan D. Desautels, Johan van Lierop, Natalie F. Huls, Andrew J. Jackson, Cordula Gruettner, Robert Ivkov
Time-dependent relaxation of nanomagnets, such as magnetic nanoparticles, have applications in many disciplines of science and technology because these magnets can exhibit hysteresis and loss power when exposed to AC magnetic fields. In particular, the

Particle Moment Canting in CoFe 2 O 4 Nanoparticles

November 19, 2014
Author(s)
K. Hasz, Y. Ijiri, Kathryn L. Krycka, Julie Borchers, R. A. Booth, S. Oberdick, S. A. Majetich
Polarization-analyzed small-angle neutron scattering methods are used to determine the spin morphology in high crystalline anisotropy, 11 nm diameter CoFe 2O 4 nanoparticle assemblies with randomly oriented easy axes. In moderate to high magnetic fields

Origin of Surface Canting Within Fe 3 O 4 Nanoparticles

October 2, 2014
Author(s)
Kathryn L. Krycka, Julie A. Borchers, R. A. Booth, Y. Ijiri, K. Hasz, J. J. Rhyne, S. A. Majetich
The nature of near-surface spin canting within Fe 3O 4 nanoparticles is highly debated. Here we develop a neutron scattering asymmetry analysis which quantifies the spin canting angle to between 23° and 42° at 1.2 T. Simultaneously, an energy-balance model