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Search Publications by: Jose A Rodriguez (Assoc)

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Displaying 76 - 100 of 102

Quantum Critical Fluctuations in the Heavy Fermion compound Ce(Ni^s0.935^Pd 0.065 ) 2 Ge 2

December 3, 2014
Author(s)
C. H. Wang, L. Poudel, A. E. Taylor, J .M. Lawrence, A. D. Christianson, Sung Chang, Jose Rodriguez Rivera, Jeffrey W. Lynn, A. A. Podlesnyak, G. Ehlers, R. E. Baumbach, E. D. Bauer, K. Gofryk, F. Ronning, K. J. McClellan, J. D. Thompson
Inelastic neutron scattering experiments were performed on a single crystal of the heavy Fermion compound Ce(Ni 0.935Pd 0.065) 2Ge 2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). We find that the

Magnetic Ordering induced by Interladder Coupling in the Spin-1/2 Heisenberg Two-leg Ladder Antiferromagnet C 9 H 18 N 2 CuBr 4

May 30, 2014
Author(s)
Tao Hong, K. P. Schmidt, K. Coester, F.F. Awwadi, M.M. Turnbull, Yiming Qiu, Jose Rodriguez Rivera, M. Zhu, X. Ke, C.P. Aoyama, Y. Takano, Huibo Cao, W. Tian, J. Ma, R. Custelcean, H.D. Zhou, M. Matsuda
We present specific-heat and neutron-scattering results for the S=1/2 quantum antiferromagnet (dimethylammonium)(3,5-dimethylpyridinim)CuBr 4. The material orders magnetically at Τ N=1.99(2)K, and magnetic excitations are accompanied by an energy gap of 0

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

Molecular Quantum Magnetism in LiZn 2 Mo 3 O 8

January 15, 2014
Author(s)
M. Mourigal, W. T. Fuhrman, J. P. Sheckelton, A. Wartelle, Jose Rodriguez Rivera, D. L. Abernathy, T. M. McQueen, Collin L. Broholm
Inelastic neutron scattering at temperatures below 30 K from a powder of LiZn 2Mo 3O 8 demonstrates this triangular-lattice antiferromagnet hosts collective magnetic excitations from spin 1⁄2 Mo 3O 13 molecules. The excitation spectrum, that appears

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

Common Origin of the Two Types of Magnetic Fluctuations in Iron Chalcogenides

December 5, 2011
Author(s)
Songxue Chi, Jose Rodriguez Rivera, Jeffrey W. Lynn, Chenglin Zhang, D. Phelan, Deepak Singh, Rick L. Paul, Pengcheng Dai
We use inelastic neutron scattering to study the low energy spin excitations in moderately doped non-superconducting Fe 1.01Te 0.72Se 0.28. The spin excitations in this system contain components near (0.5,0,0) and (0.5, 0.5,0) in a-b plane reciprocal

Field-induced Quantum Fluctuations in the Heavy Fermion Superconductor CeCu 2 Ge 2

October 13, 2011
Author(s)
Deepak Singh, A. Thamizhavel, Jeffrey W. Lynn, S. K. Dhar, Jose A. Rodriguez, Tobias K Herman
Quantum-mechanical fluctuations in strongly correlated electron systems cause unconventional phenomena such as non-Fermi liquid behavior, and arguably high temperature superconductivity. Here we report the discovery of a field-tuned quantum critical

Magnetic Field Effect on the Static Antiferromagnetic Order and Spin Excitations in Underdoped Iron Arsenide Superconductor BaFe 1.92 Ni 0.08 As 2

March 14, 2011
Author(s)
Miaoyin Wang, Huiqian Luo, Meng Wang, Song Xue Chi, Jose Rodriguez Rivera, Deepak Singh, Sung Chang, Jeffrey W. Lynn, Pengcheng Dai
We use neutron scattering to study the magnetic field effect on the static antiferromagnetic (AF) order and low-energy spin excitations in the underdoped iron arsenide superconductor BaFe 1.92Ni 0.08As 2. At zero field, superconductivity that occurs below

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