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Search Publications by: Stephen E. Russek (Fed)

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Displaying 26 - 50 of 170

Stochastic Single Flux Quantum Neuromorphic Computing using Magnetically Tunable Josephson Junctions

October 16, 2016
Author(s)
Stephen E. Russek, Christine A. Donnelly, Michael Schneider, Burm Baek, Matthew Pufall, William Rippard, Pete Hopkins, Paul Dresselhaus, Samuel P. Benz
Abstract— Single flux quantum (SFQ) circuits form a natural neuromorphic technology with SFQ pulses and superconducting transmission lines simulating action potentials and axons, respectively. Here we present a new component, magnetic Josephson junctions

Comparison of T1 measurement using ISMRM/NIST system phantom

May 9, 2016
Author(s)
Kathryn E. Keenan, Karl F. Stupic, Michael A. Boss, Stephen E. Russek, Thomas L. Chenevert, Pottumarthi V. Prasad, Wilburn E. Reddick, Jie Zheng, Peng Hu, Edward F. Jackson
We used the ISMRM/NIST system phantom to assess variations of T1 measurements across MRI systems at 1.5 T and 3 T, to determine the repeatability and reproducibility of the T1 measurements. This study demonstrates that T1 variations from NMR-measured value

Variability and bias assessment in breast ADC measurement across multiple systems

February 29, 2016
Author(s)
Kathryn E. Keenan, Sheye O. Aliu, Lisa J. Wilmes, David C. Newitt, Ella F. Jones, Wen Li, Michael A. Boss, Karl F. Stupic, Stephen E. Russek, Nola M. Hylton
Purpose: To assess the ability of a recent, anatomically designed breast phantom incorporating T 1 and diffusion elements to serve as a quality control device for quantitative comparison of apparent diffusion coefficient (ADC) measurements calculated from

Dynamics of Magnetic Nanoparticles and Nanodevices

May 31, 2015
Author(s)
Stephen E. Russek, Eric R. Evarts, Robert J. Usselman
Nanoscale magnetic devices and particles are being developed for a wide variety of applications including magnetic memory, nanoscale sensors, magnetic resonance imaging (MRI) agents, and therapeutic agents. Magnetic nanoparticles are also endogenous to the

On-wafer Magnetic Resonance of Magnetite Nanoparticles

May 11, 2015
Author(s)
Charles A. Little, Stephen E. Russek, James C. Booth, Pavel Kabos, Robert J. Usselman
Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nl) and a small numbers of spin (1 nmole). On

Terbium-Doped Magnetite Nanocrystals for Multimodal Imaging Agents

May 1, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin M. Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans T. Nembach, Elke Arenholz, Yves Idzerda
High quality cubic Tb-doped magnetite nanocrystals have been fabricated and have shown that the Tb is incorporated into the octahedral 3+ sites. Magnetization and FMR data indicate that the Tb spins are weakly coupled to the iron spin lattice at room

Nanoscale Spin Valve Josephson Junction Devices

April 14, 2015
Author(s)
Burm Baek, William H. Rippard, Matthew R. Pufall, Samuel P. Benz, Stephen E. Russek, Horst Rogalla, Paul D. Dresselhaus
Traditionally, superconductivity and magnetism have had a mutually exclusive relationship. However, the physics of superconductor-ferromagnet hybrid structures turned out to be far from being simply destructive, which has led to the hope of a new breed of

Temperature-dependent structure of Tb-doped magnetite nanoparticles

February 13, 2015
Author(s)
Katherine P. Rice, Stephen E. Russek, Roy H. Geiss, Justin Shaw, Robert J. Usselman, Eric R. Evarts, Thomas J. Silva, Hans Nembach, Elke Arenholz, Yves U. Idzerda
High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a modified wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the

Spin-transfer torque switching observed in nanopillar superconducting-magnetic hybrid Josephson junctions

January 9, 2015
Author(s)
Burm Baek, William H. Rippard, Matthew R. Pufall, Samuel P. Benz, Stephen E. Russek, Horst Rogalla, Paul D. Dresselhaus
Combining superconducting and magnetic materials to create novel superconducting devices has been motivated by the discovery of the Josephson critical current (Ics) oscillations with magnetic layer thickness and the demonstration of devices with switchable

High-Relaxivity Superparamagnetic Iron Oxide Nanoworms with Decreased Immune Recognition and Long-Circulating Properties

November 24, 2014
Author(s)
Stephen E. Russek, Guankui Wang, Swetha Inturi, Natalie J. Serkova, Sergey Merkulov, Keith McCrae, Nirmal K. Banda, Dmitri Simberg
One of the core issues of nanotechnology involves masking the foreignness of nanomaterials to enable in vivo longevity and long-term immune evasion. Dextran-coated superparamagnetic iron oxide nanoparticles are very effective magnetic resonance imaging

A Design-of-Experiments Approach to FEM Uncertainty Analysis for Optimizing Magnetic Resonance Imaging RF Coil Design

October 10, 2014
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Li Ma, Karl F. Stupic, Kathryn E. Keenan, Stephen E. Russek
Using the RF module of COMSOL, we compute the magnetic flux density norm (BN) profiles for frequencies in the 76 to 100 MHz range, inside of a prototype birdcage coil, courtesy of Japan's National Institute of Radiological Sciences (NIRS), loaded with a

Hybrid superconducting-magnetic memory device using competing order parameters

May 28, 2014
Author(s)
Burm Baek, William H. Rippard, Samuel P. Benz, Stephen E. Russek, Paul D. Dresselhaus
The quantum behavior of Josephson junctions is often exploited to produce superconducting devices with outstanding performance. Josephson junctions can also be used in circuits that perform logic operations in picoseconds and may enable high-performance

Prototype Phantoms for Characterization of Ultra-Low Field Magnetic Resonance Imaging

November 26, 2013
Author(s)
Michael A. Boss, John A. Mates, Sarah E. Busch, Paul SanGiorgio, Stephen E. Russek, Kai Buckenmaier, Kent D. Irwin, Hsiao-Mei Cho, Gene C. Hilton, John Clarke
Purpose: Prototype phantoms were designed, constructed, and characterized for the purpose of calibrating ultralow field magnetic resonance imaging (ULF MRI) systems. The phantoms were designed to measure spatial resolution and to quantify sensitivity to

Microfluidic Platform for Magnetic Nanoparticle Trapping and Detection

July 15, 2013
Author(s)
Charles A. Little, John Pellegrino, Stephen E. Russek
We evaluate giant magnetoresistance (GMR) sensors to trap and count small concentrations of magnetic nanoparticles (MNPs) within microfluidic flow. The device presented in this paper takes the novel approach of capturing and detecting MNPs utilizing the

Properties of magnetic barrier structures for superconducting-magnetic hybrid Josephson junctions

July 7, 2013
Author(s)
Burm Baek, Samuel P. Benz, William H. Rippard, Stephen E. Russek, Paul D. Dresselhaus, Horst Rogalla, Matthew R. Pufall
If Josephson and spintronic technologies can be successfully integrated to produce a cryogenic memory that can be controlled with single-flux quantum pulses, then they may enable ultra-low-power, high-speed computing. We have developed hybrid Josephson

Spin-Transfer Nano-Oscillators

January 7, 2013
Author(s)
Stephen E. Russek, Ranko R. Heindl, Thomas Cecil, William H. Rippard
Spin transfer nano-oscillators are small multilayer magnetic devices that undergo microwave oscillations and output a microwave voltage when a bias current is applied. The oscillation frequency is tunable, over a range of 0.5 GHz to 225 GHz, by varying the

Single bead detection with a NMR micro capillary probe

December 6, 2012
Author(s)
Yoshihiro Nakashima, Michael A. Boss, Stephen E. Russek, John M. Moreland
We have developed a nuclear magnetic resonance (NMR) microcapillary probe for the detection of single magnetic microbeads. The geometry of the probe has been optimized so that the signal from the background water has a similar magnitude compared to the

Controlled transport of superparamagnetic beads with spin-valves

October 7, 2011
Author(s)
Wendy R. Altman, John M. Moreland, Stephen E. Russek, Bruce W. Han, Victor M. Bright
Trapping, release, and transport of individual or ensembles of 2.8 υm superparamagnetic beads functionalized with streptavidin were demonstrated using an addressable and non-volatile array of spin-valve (SV) traps integrated into a microfluidic channel

Optimization of spin-valve parameters for magnetic bead trapping and manipulation

February 6, 2010
Author(s)
Wendy R. Altman, John M. Moreland, Stephen E. Russek, Victor M. Bright
Magneto-optic Kerr effect (MOKE) and magnetoresistance (MR) measurements were used to measure the switching characteristics of spin-valve (SV) arrays currently being developed to trap and release superparamagnetic beads within a fluid medium. The effect of