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Displaying 2651 - 2675 of 3362

Model for the Bipolar Amplification Effect

December 10, 2021
Author(s)
James Ashton, Stephen Moxim, Ashton Purcell, Patrick Lenahan, Jason Ryan
We present a model based on Fitzgerald-Grove surface recombination for the bipolar amplification effect (BAE) measurement, which is widely utilized in electrically detected magnetic resonance (EDMR) to measure reliability and performance-limiting interface

Progress towards comparison of quantum and classical vacuum standards

September 22, 2021
Author(s)
Daniel Barker, Nikolai Klimov, Eite Tiesinga, James A. Fedchak, Julia Scherschligt, Stephen Eckel
We present our progress towards a comparison of NIST's cold atom primary vacuum standard and a dynamic expansion vacuum standard. The cold atom vacuum standard (CAVS) converts the loss rate of atoms from a magnetic trap to a vacuum pressure using ab initio

AC and DC Quantized Hall Array Resistance Standards

August 28, 2020
Author(s)
Randolph E. Elmquist, Mattias Kruskopf, Dinesh K. Patel, I Fan Hu, Chieh-I Liu, Albert F. Rigosi, Alireza R. Panna, Shamith U. Payagala, Dean G. Jarrett
Quantized Hall array resistance standards (QHARS) span values from 100 (ohm) to 1 M(ohm) and demonstrate precision approaching that of single devices. This paper focuses on QHARS having values near 1 k(ohm) for increased sensitivity using room-temperature

The Design of an Instrument to Realize Small Torque at NIST

August 22, 2020
Author(s)
Leon S. Chao, Rafael Marangoni, Frank C. Seifert, Darine El Haddad, Jon R. Pratt, David B. Newell, Stephan Schlamminger
… and examined for feasibility. With careful attention to magnet design, a robust and easy to implement torque …

An atomic sensor for direct detection of weak microwave signals

August 16, 2019
Author(s)
Vladislav Gerginov, Fabio C. da Silva, Craig Nelson, Archita Hati
This paper demonstrates direct detection of weak signals at microwave frequencies based on parametric frequency conversion. The atomic medium is optically pumped by a resonant light field and prepared in a coherent atomic superposition by a weak microwave

Field-Polarization Sensitivity in rf Atomic Magnetometers

February 4, 2019
Author(s)
Vladislav P. Gerginov
We demonstrate the sensitivity of an optically-pumped atomic RF magnetometer to the polarization state of the detected RF magnetic field, and measure 33 dB difference in amplitude sensitivity for opposite circular field polarizations. This sensitivity

A Backscatter-Suppressed Beta Spectrometer

June 16, 2017
Author(s)
Maynard S. Dewey, Taufique Hassan, Fred B. Bateman, Brian Collett, Guillaume Darius, Christina DeAngelis, Gordon L. Jones, Alexander Komives, Alexander Laptev, Michael Mendenhall, Jeffrey S. Nico, George Noid, Ed Stephenson, Fred Wietfeldt, Isaac Stern, Bob Trull
Backscatter of electrons from a beta spectrometer, with incomplete energy deposition, can lead to undesirable effects in many types of experiments. We present and discuss the design and operation of a backscatter-suppressed beta spectrometer that was

Disordered Route to the Coulomb Quantum Spin Liquid: Random Transverse Fields on Spin Ice in Pr 2 Zr 2 O 7

March 8, 2017
Author(s)
J.-J. Wen, S.M. Koohpayeh, K. A. Ross, B. A. Trump, T. M. McQueen, K. Kimura, S. Nakatsuji, Yiming Qiu, D. M. Pajerowski, John R. Copley, Collin L. Broholm
Inelastic neutron scattering reveals a broad continuum of excitations in Pr 2Zr 2O 7, the temperature and magnetic field dependence of which indicate a continuous distribution of quenched transverse fields (Δ}) acting on the non-Kramers Pr 3+ crystal

Localization and electron-electron interactions in few-layer epitaxial graphene

May 28, 2014
Author(s)
Randolph E. Elmquist, Fan-Hung Liu, Lung-I Huang, Yasuhiro Fukuyama, Chi-Te Liang, Yanfei Yang
We study the quantum corrections caused by electron-electron (e-e) interactions and localization to the conductivity in few-layer epitaxial graphene, in which the carriers responsible for transport are massive. Our results demonstrate that the diffusive

Friedel-like Oscillations from Interstitial Iron in Superconducting Fe 1+y Te 0.62 Se 0.38

March 7, 2012
Author(s)
V. Thampy, J. Kang, Jose Rodriguez Rivera, W. Bao, A. T. Savici, J. Hu, T. J. Liu, B. Qian, D. Fobes, Z. Q. Mao, C. B. Fu, Wangchun Chen, Q. Ye, Ross Erwin, Thomas R. Gentile, Z. Tesanovic, Collin L. Broholm
Using polarized and unpolarized neutron scattering we show that interstital Fe in superconducting Fe 1=yTe 1-xSe x induces a magnetic Friedel-like oscillation that idffracts at Q = (1⁄20) and involves greater than}50 neighboring Fe sites. The interstitial

Formation of stacking faults and their correlation with flux-pinning and critical current density for Sm-doped YBa2Cu3O7-x films

June 29, 2011
Author(s)
Winnie K. Wong-Ng, Sung H. Wee, Eliot D. Specht, Claudia Cantoni, Jonathan Zuegel, Victor Maroni, Guangyao Liu, Timothy J. Haugan, Amit Goyal
A correlation between flux-pinning characteristics and stacking faults (SFs) formed by Sm substitution on Y and Ba sites was found in Sm-doped YBCO films. It was confirmed that “223” type SFs, Y2Ba2Cu3Ox, composed of Y and O extra planes aligned parallel

IMMOBILIZED ENZYME CATALYZED POLYMERIZATION REACTIONS IN MICROREACTORS

January 1, 2010
Author(s)
Santanu S. Kundu, Atul Bhangale, William E. Wallace, Kathleen M. Flynn, Richard Gross, Kathryn L. Beers
Application of microreactor technologies enable improved safety, selectivity and yield in a range of chemical reactions in addition to new measurement methods that are often faster, cheaper and more accurate than traditional methods. In this study we have

Spin Transfer Precessional Dynamics in Co 60 Fe 20 B 20 Nanocontacts

March 14, 2008
Author(s)
William H. Rippard, Matthew R. Pufall, Michael L. Schneider, Kevin Garello, Stephen E. Russek
We report on the precessional dynamics in spin transfer oscillators having Co 60Fe 20B 20 free layers as a function of annealing time at 225 °C. Repeated annealing reduces the critical current I c by roughly a factor of 3 and increases the tunability of

Superconducting transition edge sensor using dilute AlMn alloys

July 6, 2004
Author(s)
Steven Deiker, William B. Doriese, Gene C. Hilton, Kent D. Irwin, William H. Rippard, Joel N. Ullom, Leila R. Vale, Steve T. Ruggiero, Anthony Williams, B. Young
We have fabricated a bolometer using a transition-edge sensor (TES) made of Al doped with Mn to suppress the superconducting critical temperature !Tc" of Al from #1 K to #100 mK. The resulting detector exhibits low-frequency noise consistent with theory

Observation of Reduced Three-Body Recombination in a Fermionized 1D Bose Gas

May 14, 2004
Author(s)
B L. Tolra, K M. O'Hara, J H. Huckans, William D. Phillips, S L. Rolston, James V. Porto
We investigate correlation properties of a one-dimensional interacting Bose gas by loading a mangnetically trapped 87Rb Bose-Einstein condensate into a deep two-dimensional optical lattice. We measure the three-body recombination rate for both the BEC in

2 2 S 1/2 Transition of Atomic Lithium by Doppler-Free Two-Photon Spectroscopy

January 1, 2003
Author(s)
W DeGraffenreid, Craig J. Sansonetti
We have investigated the 2 2S1/2 - 4 2S1/2 two-photon transition in atomic lithium by high resolution laser spectroscopy. The frequencies of the two-photon resonances have been measured with an accuracy of better than 1 MHz using our Fabry-Perot wavemeter

RF Material Characterization Using a Large-Diameter (76.8 mm) Coaxial Air Line

May 1, 2000
Author(s)
Chriss A. Jones, John H. Grosvenor Jr, Claude Weil
We report the development of a 76.84 mm (3.025 in) diameter coaxial air line system whose purpose is to measure the dielectric and magnetic properties of bulk dielectric and ferrite materials over a frequency range of approximately 0.3 - 1500 MHZ. We
Displaying 2651 - 2675 of 3362
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