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Search Publications by: Juscelino Leao (Fed)

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Displaying 26 - 40 of 40

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

High-Pressure Neutron Scattering of the Magnetoelastic Ni-Cr Prussian Blue Analog

March 3, 2015
Author(s)
Daniel M Pajerowski, S. E. Conklin, Juscelino Leao, Leland Harriger, D. Phelan
This paper summarizes 0 GPa to 0.6 GPa neutron diffraction measurements of a nickel hexacyanochromate coordination polymer (NiCrPB) that has the face-centered cubic, Prussian blue structure. Deuterated powders of NiCrPB contain approximately equal}100 nm

Boson Peak in Deeply Cooled Confined Water: A Possible Way to Explore the Existence of the Liquid-to-Liquid Transition in Water

June 13, 2014
Author(s)
Zhe Wang, Kao-Hsiang Liu, Peisi Le, Mingda Li, Wei-Shan Chiang, Juscelino Leao, John R. Copley, Madhu Sudan Tyagi, Andrey Podlesnyak, Alexander I. Kolesnikov, Chung-Yuan Mou, Sow-Hsin Chen
The Boson peak in deeply-cooled water confined in nanopores is studied with inelastic neutron scattering. We show that the emergence of the Boson peak is correlated to the Widom line below 1600 bar. Above 1600 bar, the situation is different and from this

Phase Transitions in K-doped MoO 2

May 30, 2014
Author(s)
L.M.S. Alves, B.S. de Lima, C.A.M. dos Santos, A. Rabello, S.H. Masunaga, J. J. Neumeier, Juscelino Leao
K 0.05MoO 2 has been studied by x-ray and Neutron diffractometry, electrical resistivity, magnetization, heat cpacity, and thermal expansion measurements. The compound displays two phase transitions, a first order phase transition near room temperature and

Role of Random Electric Fields in Relaxors

February 14, 2014
Author(s)
Daniel P. Phelan, Christopher Stock, Jose Rodriguez Rivera, Songxue Chi, Juscelino Leao, Xifa Long, Yujuan Xie, Alexei A. Bokov, Zuo-Guang Ye, Panchapakesan Ganesh, Peter M. Gehring
Pb(Zr 1¿xTi x)O 3 (PZT) and Pb[(Mg 1/3Nb 2/3) 1¿xTi x]O 3 (PMN-xPT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudo-rhombohedral compositions near a tetragonal phase boundary. In PZT these compositions are

Safety Interlock and Vent System to Alleviate Potentially Dangerous Ice Blockage of Top-loading Cryostat Sample Sticks

August 1, 2013
Author(s)
S. Pangelis, S. R. Olsen, Julia Scherschligt, Juscelino Leao, S. A. Pullen, Daniel C Dender, J. R. Hester, P. Imperia
A combined solution is presented for minimising the safety hazards associated with closed cycle cryostats described in Swainson & Cranswick (2010) J. Appl. Cryst. 43, 206-210. The initial solution is to install a vent tube witn one open end deep inside the

Neutron Scattering Study of a Quasi-2D Spin-1/2 Dimer System Piperazinium Hexachlorodicuprate Under Hydrostatic Pressure

November 22, 2010
Author(s)
Tao Hong, Chris Stock, I. Cabrera, Collin L. Broholm, Yiming Qiu, Juscelino Leao, Sarah Poulton, John R. Copley
We report inelastic neutron scattering study of a quasi-two-dimensional S=1/2 dimer system Piperazinium Hexachlorodicuprate under hydrostatic pressure. The spin gap δ becomes softened with the increase of the hydrostatic pressure while the bandwidth of the

Coupled magnetic and ferroelectric hysteresis in multiferroic Ni ^ d3 ^ V ^ d2 ^ O ^ d8 ^

August 18, 2009
Author(s)
I. Cabrera, M. Kenzelmann, Wangchun Chen, Ross Erwin, Thomas R. Gentile, Juscelino Leao, Jeffrey W. Lynn, N. Rogado, R. J. Cava, C. Broholm, G. Lawes, Ying Chen
Electric control of spin chirality in a magnetically frustrated multiferroic is demonstrated through polarized magnetic neutron diffraction. Cooling to the cycloidal multiferroic phase of Ni ^ d3 ^ V ^ d2 ^ O ^ d8 ^ in an electric field causes the

Pressure-induced volume-collapsed tetragonal phase of CaFe 2 As 2 as seen via neutron scattering

November 24, 2008
Author(s)
A. Kreyssig, Mark Green, Y. Lee, G. D. Samolyuk, Pawel Zajdel, Jeffrey Lynn, S. L. Bud'ko, M. S. Torikachvili, N. Ni, S. Nandi, Juscelino Leao, Sarah Poulton, D. N. Argyriou, B. N. Harmon, R. J. McQueeny, P. C. Canfield, A. I. Goldman
Recent investigations of the superconducting iron-arsenide families have highlighted the role of pressure, be it chemical or mechanical, in fostering superconductivity. Here we report that CaFe2As2 undergoes a pressure-induced transition to a nonmagnetic