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Search Publications by: Shannon Watson (Fed)

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Displaying 1 - 20 of 20

Optimizing Magnetically Shielded Solenoids for Large Volume 3 He Neutron Spin Filters

October 2, 2020
Author(s)
Wangchun Chen, Md. Hassan, Ross Erwin, Shannon M. Watson, Thomas R. Gentile, G. L. Jones
An important consideration when designing a magnetostatic cavity for various applications is to maximize the ratio of the volume of field homogeneity to the overall size of the cavity. We report a design of a magnetically shielded solenoid that

Wide-Angle Polarization Analysis on the Multi-Axis Crystal Spectrometer for the Study of Collective and Single Particle Dynamics of Methanol at its Prepeak

July 1, 2019
Author(s)
Wangchun Chen, Shannon M. Watson, Yiming Qiu, Jose Rodriguez Rivera, Antonio Faraone
Neutron polarization analysis capability with a large scattering angle and momentum transfer coverage has not been widely implemented for the separation of coherent and incoherent quasi-elastic neutron scattering (QENS) spectra. A feasibility test for soft

Quantum Critical Behavior in Ce(Fe 0.76 Ru 0.24 ) 2 Ge 2

May 7, 2019
Author(s)
Wouter Montfrooij, Tom Heitmann, Yiming Qiu, Shannon M. Watson, Ross Erwin, Wangchun Chen, Yang Zhao, Meigan Aronson, Yingkai Huang, Anne de Visser
Systems with embedded magnetic ions that exhibit a competition between magnetic order and disorder down to absolute zero can display unusual low temperature behaviors of the resistivity, hyperscaling behavior in which the relaxation back to equilibrium

Higgs Amplitude Mode in a Two-Dimensional Quantum Antiferromagnet near the Quantum Critical Point0

July 4, 2017
Author(s)
Tao Hong, Masashige Matsumoto, Yiming Qiu, Wangchun Chen, Thomas R. Gentile, Shannon M. Watson, Firas F. Awwadi, Mark M. Turnbull, Sachith E. Dissanayake, Harish Agrawal, Rasmus Toft-Petersen, Bastian Klemke, Kris Coester, Kai P. Schmidt, David A Tennant
Spontaneous symmetry-breaking quantum phase transitions play an essential role in current condensed matter physics 1-3. The collective excitations in the broken-symmetry phase near the quantum critical point can be characterized by fluctuations of phase

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

Identification of the Low-Energy Excitations in a Quantum Critical System

December 20, 2016
Author(s)
Tom Heitmann, Jagat Lamsal, Shannon M. Watson, Ross Erwin, Wangchun Chen, Yang Zhao, Wouter Montfrooij
We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Cd(Fe 0.76Ru 0.24) 2Ge 2 displays dynamical scaling in the

Recent Advancements of Wide-Angle Polarization Analysis with 3 He neutron Spin Filters

October 10, 2016
Author(s)
WangChun Chen, Thomas R. Gentile, Qiang NMN Ye, A. Kirchhoff, Shannon Watson, Jose A. Rodriguez, Yiming Qiu, Collin L. Broholm
Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over

3 He Spin Filter Based Polarized Neutron Capability at the NIST Center for Neutron Research

July 24, 2014
Author(s)
WangChun Chen, Thomas R. Gentile, Ross W. Erwin, Shannon Watson, Qiang NMN Ye, Kathryn L. Krycka, Brian B. Maranville
A 3He neutron spin filter (NSF) program for polarized neutron scattering was launched in 2006 as part of the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) Expansion Initiative. The goal of the project was to

Wide Angle Polarization Analysis with Neutron Spin Filters

April 29, 2013
Author(s)
Qiang NMN Ye, Thomas R. Gentile, Jeffrey R. Anderson, Collin L. Broholm, WangChun Chen, Z DeLand, Ross W. Erwin, C. B. Fu, John E. Fuller III, Aaron V. Kirchhoff, J. A. Rodriguez-Rivera, V. Thampy, T G. Walker, Shannon Watson
We report substantial improvements in a compact wide angle neutron spin filter system that was recently employed on the Multi-Axis Crystal Spectrometer at the Center for Neutron Research at the U.S. National Institute of Standards and Technology. The

Local Weak Ferromagnetism in Single-Crystalline Ferroelectric BiFeO 3

November 1, 2011
Author(s)
M. Ramazanoglu, M. Laver, William D. Ratcliff, Shannon M. Watson, Wangchun Chen, Andrew Jackson, Karunakar NMN Kothapalli, Seongsu Lee, S.- W. Cheong, V. Kiryukhin
Polarized small-angle neutron scattering studies of single-crystalline multiferroic BefeO 3 reveal a long-wavelength spin density wave generated by 1° spin canting of the spins out of the rotation plane of the antiferromagnetic cycloidal order. This

Nanometer Size Magnetic Domains and Coherent Magnetization Reversal in a Giant Exchange Bias System

August 23, 2011
Author(s)
C. Dufour, M .R. Fitzsimmons, Julie Borchers, M. Laver, Kathryn L. Krycka, K. Dumesnil, Shannon M. Watson, Wangchun Chen, S. Singh
We present compelling evidence obtained with small angle scattering of unpolarized and polarized neutron beams the magnetization reversal occurs via formation of 10-100's nm sized magnetic domains in an exchanged biased DyFe 2/YFed2^ superlattice. The

Polarized He-3 cell development and application at NIST

June 14, 2011
Author(s)
Thomas R. Gentile, WangChun Chen, Changbo Fu, Shannon Watson, Gordon L. Jones, J. W. McIver, D. R. Rich
Over a period of well over a decade, a large number and variety of polarized 3He cells for neutron applications have been developed and tested at the U.S. National Institute of Standards and Technology (NIST). These cells have primarily been employed for

A Wide Angle Neutron Spin Filter System Using Polarized 3He

October 16, 2010
Author(s)
Changbo Fu, Thomas R. Gentile, Wangchun Chen, Ross Erwin, Shannon M. Watson, Collin L. Broholm, Jose Rodriguez Rivera, Julia Scherschligt, G L. Jones
Polarized 3He neutron spin filters can operate over a wide neutron energy range and provide a large angular acceptance. A compact 3He neutron spin filter system has been developed for the Multi Axis Crystal Spectrometer at the NIST Center for Neutron

Vertically Graded Anisotropy in Co/Pd Multilayers

March 8, 2010
Author(s)
Brian J. Kirby, Joseph E. Davies, Kai Liu, Shannon Watson, G. T. Zimanyi, Robert D. Shull, Paul A. Kienzle, Julie A. Borchers
It has been theoretically predicted that depth-grading the magnetic anisotropy in perpendicular magnetic media should reduce the field required to write data, without affecting the thermal stability. To study this prediction, we have produced a series of