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Displaying 1 - 25 of 36

Influence of Hard/Soft Layer Ordering on Magnetization Reversal of Bimagnetic Nanoparticles: Implications for Biomedical/Theranostic Applications

June 14, 2023
Author(s)
Corisa Kons, Kathryn L. Krycka, Joshua Robles, Nikolaos Ntallis, Manuel Pereiro, Manh-Huong Phan, Hariharan Srikanth, Julie A. Borchers, Dario A. Arena
We investigate the spatial distribution of spin orientation in magnetic nanoparticles consisting of hard and soft magnetic layers. The nanoparticles are synthesized in a core / shell spherical morphology where the magnetically hard, high anisotropy layer

The Effect of Organic Coatings in the Magnetization of CoFe 2 O 4 Nanoparticles

August 4, 2022
Author(s)
Priscyla L. Andrade, Valdeene Silva, Kathryn L. Krycka, Juscelino Leao, I-Lin Liu, Maria P. Silva, J. Albino Aguiar
Cobalt ferrite has attracted considerable attention in recent years due to the unique physical properties such as high Curie temperature, large magnetocrystalline anisotropy, high coercivity, moderate saturation magnetization, large magnetostrictive

Chemically Induced Magnetic Dead Shells in Superparamagnetic Ni Nanoparticles Deduced from Polarized Small-Angle Neutron Scattering

July 17, 2022
Author(s)
Bhaskar Das, Joseph Batley, Kathryn L. Krycka, Julie A. Borchers, Patrick Quarterman, Caroline Korostynski, My Nguyen, Ishita Kamboj, Eray Aydil, Chris Leighton
Advances in synthesis and characterization of colloidal magnetic nanoparticles (NPs) have yielded great gains in the understanding of their complex magnetic behavior, with implications for numerous applications. Recent work using Ni NPs as a model soft

Magnetic Particle Self-Assembly at Functionalized Interfaces

April 13, 2021
Author(s)
Apurve Saini, Katharina Theis-Brohl, Alexandros Koutsioubas, Kathryn L. Krycka, Julie Borchers, Max Wolff
We study the assembly of magnetite nanoparticles in water-based ferrofluids in wetting layers close to silicon substrates with different functionalization without and with an out-of-plane magnetic field. For particles of nominal sizes 5 nm, 15 nm and 25 nm

Field-Induced Topological Hall Effect and Double-Fan Spin Structure with a c-Axis Component in the Metallic Kagome Antiferromagnetic Compound YMn 6 Sn 6

January 12, 2021
Author(s)
Qi Wang, Kelly J. Neubauer, Chunruo Duan, Qiangwei Yin, Satoru Fujitsu, Hideo Hosono, Feng Ye, Rui Zhang, Songxue Chi, Kathryn L. Krycka, Hechang Lei, Pengcheng Dai
The geometrical frustration nature of the kagome lattice makes it a great host to flat electronic band, non-trivial topological properties, and novel magnetisms. Metallic kagome antiferromagnet YMn 6Sn 6 exhibits the topological Hall effect (THE) when an

Layering of Magnetic Nanoparticles at Amorphous Magnetic Templates with Perpendicular Anisotropy

August 26, 2020
Author(s)
Apurve Saini, Julie Borchers, Sebastian George, Brian B. Maranville, Kathryn L. Krycka, Joseph Dura, Katharina Theis-Brohl, Max Wolff
We reveal the assembly of monodisperse magnetite nanoparticles of sizes 5 nm, 15 nm and 25 nm from dilute water-based ferrofluids onto an amorphous magnetic template with out-ofplane anisotropy. From neutron reflectometry experiments we extract density

Cobalt Ferrite Nanoparticle Intercalated Carbon Nanotubes for a Nanomagnetic Ultrasensitive Sensor for Cr-VI in Water

June 24, 2020
Author(s)
Tassew Mekuria, Syed Khalid, Kathryn L. Krycka, Markus Bleuel, Himanshu Verma, Haiping Hong, Shashi P. Karna, Dereje Seifu
Nanocomposites of cobalt ferrite (CFO) magnetic nanoparticles intercalated on carbon nanotubes (CNTs) are evaluated as a nanomagnetic ultrasensitive sensor for the environmental toxin, hexavalent chromium (Cr-VI). Specifically, the structural and magnetic

Correlated Spin Canting in Ordered Core-Shell Fe 3 O 4 /Mn x Fe 3-x Od4^ Nanoparticle Assemblies

March 18, 2019
Author(s)
Y. Ijiri, Kathryn L. Krycka, I. Hunt-Isaak, H. Pan, J. Hsieh, Julie Borchers, James Jennings Rhyne, Samuel D. Oberdick, A. Abdelgawad, S. A. Majetich
Polarization-analyzed small-angle neutron scattering methods are used to determine the spin arrangements in ordered three-dimensional assemblies of 7.4 nm diameter core-shell Fe 3O 4/Mn xFe 3-xO 4 nanoparticles. In moderate to high magnetic fields, the

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