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Physics

Magnetics

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Displaying 1 - 25 of 290

Sampling from exponential distributions in the time domain with superparamagnetic tunnel junctions

April 22, 2025
Author(s)
Temitayo Adeyeye, Sidra Gibeault, Daniel Lathrop, Matthew Daniels, Mark Stiles, Jabez McClelland, William Borders, Jason Ryan, Philippe Talatchian, Ursula Ebels, Advait Madhavan
Though exponential distributions are ubiquitous in statistical physics and related computational models, sampling them from device behavior is rarely done. The superparamagnetic tunnel junction (SMTJ), a key device in probabilistic computing, shows

METROLOGY FOR MRI: THE FIELD YOU'VE NEVER HEARD OF

March 19, 2025
Author(s)
Kathryn Keenan, Stephen Russek, Matt Hall
Quantitative MRI has been an active area of research for decades and has produced a huge range of approaches with enormous potential for patient benefit. In many cases, however, there are challenges with reproducibility which has hampered clinical

Parallel 3D Temperature Image Reconstruction Using Multi-Color Magnetic Particle Imaging (MPI)

October 18, 2024
Author(s)
Klaus Natorf Quelhas, Mark-Alexander Henn, Ricardo Cordeiro de Farias, Weston L. Tew, Solomon I. Woods
Magnetic Particle Imaging (MPI) is a novel technique developed for remotely detecting magnetic nanoparticle (MNP) tracers, with great potential for biomedical imaging (as an alternative to traditional methods like MRI or CT), cell tracking, targeted drug

Magnetic skin effect in Pb(Fe1/2Nb1/2)O3

July 29, 2024
Author(s)
Guangyong Xu, Peter M. Gehring
Relaxor-ferroelectrics display exceptional dielectric properties resulting from the underlying random dipolar fields induced by strong chemical inhomogeneity. An unusual structural aspect of relaxors is a skin-effect where the near-surface region in single

Measurement-driven Langevin modeling of superparamagnetic tunnel junctions

July 23, 2024
Author(s)
Liam Pocher, Temitayo Adeyeye, Sidra Gibeault, Philippe Talatchian, Ursula Ebels, Daniel Lathrop, Jabez J. McClelland, Mark Stiles, Advait Madhavan, Matthew Daniels
Superparamagnetic tunnel junctions are important devices for a range of emerging technologies, but most existing compact models capture only their mean switching rates. Capturing qualitatively accurate analog dynamics of these devices will be important as

Single-Phase L10-Ordered High Entropy Thin Films with High Magnetic Anisotropy

June 28, 2024
Author(s)
Willie Beeson, Dinesh Bista, Huairuo Zhang, Sergiy Krylyuk, Albert Davydov, Gen Yin, Kai Liu
The vast high entropy alloy (HEA) composition space is promising for discovery of new material phases with unique properties. We explore the potential to achieve high magnetic anisotropy materials in single-phase HEA thin films. Thin films of FeCoNiMnCu

GPU-accelerated parallel image reconstruction strategies for magnetic particle imaging

June 24, 2024
Author(s)
Klaus Natorf Quelhas, Mark-Alexander Henn, Ricardo Farias, Weston L. Tew, Solomon I. Woods
Image reconstruction is a fundamental step in Magnetic Particle Imaging (MPI). Since it was developed, several methods have been studied to perform more efficient and accurate reconstructions. One of the challenges of MPI is the fact that the

Measurement-driven neural-network training for integrated magnetic tunnel junction arrays

May 14, 2024
Author(s)
William Borders, Advait Madhavan, Matthew Daniels, Vasileia Georgiou, Martin Lueker-Boden, Tiffany Santos, Patrick Braganca, Mark Stiles, Jabez J. McClelland, Brian Hoskins
The increasing scale of neural networks needed to support more complex applications has led to an increasing requirement for area- and energy-efficient hardware. One route to meeting the budget for these applications is to circumvent the von Neumann

Neural networks three ways: unlocking novel computing schemes using magnetic tunnel junction stochasticity

September 28, 2023
Author(s)
Matthew Daniels, William Borders, Nitin Prasad, Advait Madhavan, Sidra Gibeault, Temitayo Adeyeye, Liam Pocher, Lei Wan, Michael Tran, Jordan Katine, Daniel Lathrop, Brian Hoskins, Tiffany Santos, Patrick Braganca, Mark Stiles, Jabez J. McClelland
Due to their interesting physical properties, myriad operational regimes, small size, and industrial fabrication maturity, magnetic tunnel junctions are uniquely suited for unlocking novel computing schemes for in-hardware neuromorphic computing. In this

Harmonic dependence of thermal magnetic particle imaging

September 22, 2023
Author(s)
Thinh Bui, Mark-Alexander Henn, Weston L. Tew, Megan Catterton, Solomon I. Woods
Advances in instrumentation and tracer materials are still required to enable sensitive and accurate 3D temperature monitoring by magnetic particle imaging. We have developed a magnetic particle imaging instrument to observe temperature variations using

Magnetic Resonance Imaging Biomarker Calibration Service: NMR Measurement of Isotropic Water Diffusion Coefficient

March 30, 2023
Author(s)
Stephen E. Russek, Katy Keenan, Karl Stupic, Nikki Rentz, Michael Boss, Kevin J. Coakley, Amanda Koepke, Cassandra Stoffer
This document describes a calibration service to measure the water diffusion coefficient, or diffusivity, in reference materials and tissue mimics using nuclear magnetic resonance (NMR) techniques. This calibration is restricted to materials which exhibit

Parallel MPI image reconstructions in GPU using CUDA

March 19, 2023
Author(s)
Klaus Natorf Quelhas, Mark-Alexander Henn, Ricardo Farias, Weston L. Tew, Solomon I. Woods
This work shows that it is possible to obtain faster MPI image reconstructions by implementing the algorithms in parallel in Graphics Processing Units (GPUs) using NVIDIA's CUDA (Compute Unified Device Architecture). While the parallel Kaczmarz's algorithm

Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains

December 23, 2022
Author(s)
Nanna Hagstrom, Rahul Jangid, F. N. U. Meera, Diego Turenne, Jeffrey Brock, Erik Lamb, Boyan Stoychev, Justine Schlappa, Natalia Gerasimova, Benjamin Van Kuiken, Rafael Gort, Laurent Mercadier, Loic Le Guyader, Andrey Samartsev, Andreas Scherz, Giuseppe Mercurio, Hermann Durr, Alexander Reid, Monika Arora, Hans Nembach, Justin Shaw, Emmanuelle Jal, Eric Fullerton, Mark Keller, Roopali Kukreja, Stefano Bonetti, Thomas J. Silva, Ezio Iacocca
Symmetry is a powerful concept in physics, but its applicability to far-from-equilibrium states is still being understood. Recent attention has focused on how far-from-equilibrium states lead to spontaneous symmetry breaking. Conversely, ultrafast optical

Nonlinear excitations in ferrites

November 22, 2022
Author(s)
Pavel Kabos
This book chapter describes the processes leading to nonlinear excitations in ferrites at high power levels. We start from equation of motion that include nonlinear terms leading to nonlinear processes. First and second order Suhl instabilities for