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Search Publications

NIST Authors in Bold

Displaying 18676 - 18700 of 74297

Correlation of anomalous write error rate and ferromagnetic resonance spectrum in spin-transfer-torque-magnetic-random-access-memory devices containing in-plane free layers

May 28, 2014
Author(s)
Eric R. Evarts, Ranko R. Heindl, William H. Rippard, Matthew R. Pufall
In a small fraction of magnetic-tunnel-junction-based MRAM devices with in-plane free layers, the write error rates (WERs) are higher than expected on the basis of the macrospin or quasi-uniform magnetization reversal models. In devices with increased WERs

Effect of Pnictogen Height on Spin Waves in Iron Pnictides

May 28, 2014
Author(s)
Chenglin Zhang, Leland Harriger, Zhiping Yin, Weicheng Lv, Miaoyin Wang, Guotai Tan, Yu Song, D. L. Abernathy, Wei Tian, Takeshi Egami, Kristjan Haule, Gabriel Kotliar, Pengcheng Dai
We use inelastic neutron scattering to study spin waves in the antiferromagnetic ordered phase of iron pnictide NaFeAs throughout the Brillouin zone. Comparing with the well-studied AFe 2As 2 (A = Ca,Sr,Ba) family, spin waves in NaFeAs have considerably

Evaluating the Uncertainty of Input Quantities in Measurement Models

May 28, 2014
Author(s)
Antonio M. Possolo
The Guide to the Expression of Uncertainty in Measurement gives guidance about how values and uncertainties should be assigned to the input quantities that appear in measurement models. This contribution offers a concrete proposal for how that guidance may

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

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

Experimental Study of Firebrand Transport

May 27, 2014
Author(s)
Samuel L. Manzello, Kuibin Zhou, Sayaka Suzuki
The NIST Firebrand Generator (NIST Dragon) has been used to quantify the vulnerability of structures to ignition by firebrand attack. The Firebrand Generator is also a useful device to study firebrand transport, and has been used to validate firebrand

Fe I Oscillator Strengths for the Gaia-ESO Survey

May 27, 2014
Author(s)
Matthew Ruffoni, E. A. Den Hartog, James E. Lawler, N. R. Brewer, K. Lind, Gillian Nave, J C. Pickering
The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale study of multielement chemical abundances of some 100; 000 stars in the Milky Way with the ultimate aim of quantifying the formation history and evolution of young, mature and

Ignition of Fine Fuels Exposed to Firebrand Showers

May 27, 2014
Author(s)
Samuel L. Manzello, Sayaka Suzuki, Junichi Suzuki, Koji Kagiya, Yoshihiko Hayashi
Wildland-Urban Interface (WUI) fires have caused significant destruction to communities throughout the world. WUI fires continue to burn in the USA; most recently in Texas in 2011, Colorado, and California in 2012, and Arizona, Colorado, and California in

Lithiated Primary Amine-A New Material for Hydrogen Storage

May 26, 2014
Author(s)
Juner Chen, Hui Wu, Guotao Wu, Zhitao Xiong, Ruiming Wang, Hongjun Fan, Wei Zhou, Bin Liu, Yongshen Chua, Xiahua Ju, Ping Chen
A facile method in synthesizing crystalline lithiated amines via ball milling primary amines with LiH unprecedented endothermic dehydrogenation feature in the temperature range of 150-250 Degree}C., showing potentials as a new type of hydrogen storage

Intermittent contact resonance atomic force microscopy

May 23, 2014
Author(s)
Gheorghe Stan, Richard S. Gates
The intermittent contact resonance atomic force microscopy (ICR-AFM) mode proposed here is a new frequency modulation technique performed in scanning force controlled AFM modes like force volume or peak force tapping. It consists of tracking the change in

Microsensors for Mars: Trace Analyte Detection in a Simulated Martian Environment

May 23, 2014
Author(s)
Kurt D. Benkstein, Phillip H. Rogers, Christopher B. Montgomery, C. Jin, Baranidharan Raman, Stephen Semancik
Chemiresistive microsensor arrays are being developed and tested in a simulated Martian environment. Target analyte species include trace small molecules that may indicate current geological or, potentially, biological activity on Mars. The sensing films

Acoustic Techniques for Measuring Transport Properties of Gases

May 22, 2014
Author(s)
Keith A. Gillis, Michael R. Moldover
We describe the principles, techniques, and performance of acoustic resonators used to measure the shear viscosity, the thermal conductivity, and the bulk viscosity in gases. We developed the Greenspan acoustic viscometer at NIST, where colleagues used it

Collapse of the Cross-spectral Function

May 22, 2014
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of amplitude and phase conditions

Correlation Measurements between PM and AM Noise in Oscillators

May 22, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We discuss techniques for measuring the correlation between phase modulated (PM) and amplitude modulated (AM) noise in an oscillator and report results of such correlation in a few selected oscillators of similar size, weight, power consumption and

Frequency Biases in a Cold-Atom Coherent Population Trapping Clock

May 22, 2014
Author(s)
Elizabeth A. Donley, Eric M. Blanshan, Francois-Xavier R. Esnault, John E. Kitching
A compact cold-atom clock based on coherent population trapping (CPT) has been developed. The clock typically demonstrates a short-term fractional frequency stability of 4x10 -11/√τ limited by frequency noise on the interrogation lasers. The largest two

Polar codes in a QKD Environment

May 22, 2014
Author(s)
Anastase Nakassis, Alan Mink
Polar coding is the most recent encoding scheme in the quest for error correction codes that approaches the Shannon limit, has a simple structure, and admits fast decoders. As such, it is an interesting candidate for the quantum key distribution (QKD)

A Binomial Approximation Method for the Ising Model

May 21, 2014
Author(s)
Isabel M. Beichl, Amanda A. Streib, Noah S. Streib, Francis Sullivan
A large portion of the complexity inherent to the Ising model can be captures with a trivial amount of computation. in this work, we support this claim by defining an approximation to the partition function and other thermodynamic quantities of the Ising

Advanced designs for non-imaging submillimeter-wave Winston cone concentrators

May 21, 2014
Author(s)
Andrew O. Nelson, Erich N. Grossman
We describe the design and simulation of several non-imaging concentrators designed to couple submillimeter wavelength radiation from free space into highly overmoded, rectangular, WR-10 waveguide. Previous designs are altered to improve the uniformity of
Displaying 18676 - 18700 of 74297