U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by:

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 78

Spinon Confinement and a Sharp Longitudinal Mode in Yb 2 Pt 2 Pb in Magnetic Fields

March 8, 2019
Author(s)
W. J. Gannon, I. A. Zaliznyak, L. S. Wu, A. E. Feiguin, A. M. Tsvelik, F. Demmel, Yiming Qiu, John R. Copley, M. S. Kim, M. C. Aronson
The fundamental excitation of spin chain systems is the spinon, which is a deconfined quasiparticle with fractionalized spin. Coupling spin chains leads to the confinement of these spinons, a condensed matter analog of quark confinement in quantum

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

Hydrogen Diffusion in Bulk and Nanocrystalline Palladium: A Quasielastic Neutron Scattering Study

August 29, 2016
Author(s)
Maiko Kofu, Naoki Hashimoto, Hiroshi Akiba, Hirokazu Kobayashi, Hiroshi Kitagawa, Hiroshi Kitagawa, Madhu Sudan Tyagi, Antonio Faraone, John R. Copley, Wiebke Lohstroh, Osamu Yamamuro
The diffusion dynamics of hydrogen in bulk and Nanocrystalline palladium has been examined using quasielastic neutron scattering (QENS). With respect to bulk PdH 0.73, two relaxation processes were found. For both processes, the variation of the relaxation

Dynamic Signature of Molecular Association in Methanol

July 7, 2016
Author(s)
Christopher E. Bertrand, Jeffrey L. Self, John R. Copley, Antonio Faraone
Quasielastic neutron scattering measurements and molecular dynamics simulations were combined to investigate the collective dynamics of deuterated methanol. A slow, non-Fickian mode was observed in addition to the standard heat mode. The qualitative

Orbital-Exchange and Fractional Quantum Number Excitations in an f-electron Metal Yb 2 Pt 2 Pb

June 3, 2016
Author(s)
L. S. Wu, W. J. Gannon, I. A. Zaliznyak, A. M. Tsvelik, M. Brockmann, J.-S. Caux, M. S. Kim, Yiming Qiu, John R. Copley, G. Ehlers, A. Podlesnyak, M. C. Aronson
Exotic quantum states and fractionalized magnetic excitations, such as spinons in one-dimensional chains, are generally viewed as belonging to the domain of 3d transition metal systems with spin 1/2. Our neutron scattering experiments on the 4f-electron

Magnetic Structure of Yb 2 Pt 2 Pb: Ising Moments on the Shastry-Sutherland Lattice

March 22, 2016
Author(s)
W. Miiller, L. S. Wu, M. S. Kim, T. Orvis, J. W. Simonson, M. Gamza, D. M. McNally, C. S. Nelson, G. Ehlers, A. Podlesnyak, Joel Helton, Yang Zhao, Yiming Qiu, John R. Copley, Jeffrey W. Lynn, I. Zaliznyak, M. C. Aronson
Neutron diffraction measurements were carried out on single crystals and powders of Yb 2Pt 2Pb, where Yb moments form planes of orthogonal dimers in the frustrated Shastry-Sutherland Lattice (SSL). Yb 2Pt 2Pb orders antiferromagnetically at T N=2.07 K, and

The Magnetic Transitions and Dynamics in the Multiferroic Lu 0.5 Sc 0.5 FeO 3

February 26, 2016
Author(s)
Junjie Yang, Chunruo Duan, John R. Copley, Craig Brown, Despina Louca
In spite of its frustrated lattice, the multiferroic Lu 0.5Sc 0.5FeO 3 exhibits two consecutive magnetic transitions at T% N1approximately equal to}175 K and T N2 approximately equal to}70 K determined from neutron diffraction. In the ordered state

Rotational Dynamics of Organic Cations in the CH 3 NH 3 Pbl 3 Perovskite

December 14, 2015
Author(s)
Tianran Chen, Benjamin J. Foley, Bahar NMN Ipek, Madhu Sudan Tyagi, John R. Copley, Craig Brown, Joshua J. Choi, Seunghun Lee Lee
All semiconductors can generate free charges by absorbing light. However, not all semiconductors are high performance photovoltaic materials, because the charge carriers with opposite signs, electrons and holes, quickly annihilate each other. High

Gapped and Gapless Short-Range-Ordered Magnetic States with (1/2,1/2,1/2) Wave Vectors in the Pyrochlore Magnet Tb 2+x Ti 2-X O 7+d

December 10, 2015
Author(s)
E. Kermarrec, D. D. Maharaj, J. Gaudet, K. Fritsch, D. Pomaranski, J. B. Kycia, Yiming Qiu, John R. Copley, M. M. P. Couchman, A. O. R. Morningstar, H. A. Dabkowska, B. D. Gaulin
Recent low temperature heat capacity (CP ) measurements on polycrystalline samples of the py- rochlore antiferromagnet Tb 2+xTi 2¿xO 7+δ have shown a strong sensitivity to the precise Tb con- centration x, with a large anomaly exhibited for x0.005 at TC0.5

Effects of Pressure on the Dynamics of an Oligomeric Protein from Deep-Sea Hyperthermophile

November 10, 2015
Author(s)
Utsab R. Shrestha, Debsindhu Bhowmik, John R. Copley, Madhu Sudan Tyagi, Juscelino Leao, Xiang-Qiang Chu
Inorganic Pyrophosphatase (IPPase) from Thermococcus thioreducens is a large oligomeric protein derived from a hyperthermophilic microorganism that is found near hydrothermal vents deep under the sea, where the pressure is up to 100 MPa (1 kbar). It has

Spin Jam Induced by Quantum Fluctuations in a Frustrated Magnet

September 15, 2015
Author(s)
Junjie Yang, Anjana Samarakoon, Sachith Dissanayake, Hiroaki Ueda, Israel Klich, Daniel M Pajerowski, Nicholas Butch, Qingzhen Huang, John R. Copley, Seung-Hun Lee
Since the discovery of spin glasses in dilute magnetic systems, their study has been largely focused on understanding randomness and defects as the driving mechanisms. However, it has been theoretically suggested that different mechanism. However, it has
Was this page helpful?