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Search Publications by: Jose A Rodriguez ()

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Displaying 26 - 50 of 53

Gapped Excitation in Dense Kondo Lattice CePtZn

January 10, 2017
Author(s)
Leland Weldon Harriger, Steven M.T. Disseler, J. Gunasekera, Jose A. Rodriguez, J. Pixley, P. Manfrinetti, S. K. Dhar, D. K. Singh
We report on neutron υSR scattering studies of dense Kondo lattice CePtZn. The system develops long range incommensurate magnetic order as the temperature is reduced below T N = 1.75 K. Interesting, a Q-indpenedent characteristic and its persistence to

Absence of Long-Wavelength Nematic Fluctuations in LiFeAs

December 1, 2016
Author(s)
Adrian Merritt, Jose Rodriguez Rivera, Yu Li, Weiyi Wang, Chenglin Zhang, Pengcheng Dai, Dmitry Reznik
We investigated long-wavelength nematic fluctuations in an Fe-based superconductor LiFeAs near q=(0.05,0,0) by measuring temperature-dependent renormalization of acoustic phonons through inelastic neutron scattering. We found that the phonons have

Recent Advancements of Wide-Angle Polarization Analysis with 3 He neutron Spin Filters

October 10, 2016
Author(s)
WangChun Chen, Thomas R. Gentile, Qiang NMN Ye, A. Kirchhoff, Shannon Watson, Jose A. Rodriguez, Yiming Qiu, Collin L. Broholm
Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over

Modulated Magnetism and Anomalous Electronic Transport in Ce 3 Cu 4 As 4 O 2

August 29, 2016
Author(s)
Jiakui K. Wang, Shan Wu, Yiming Qiu, Jose Rodriguez Rivera, Qingzhen Huang, Collin L. Broholm, E. Morosan
The complex magnetism and transport properties of tetragonal Ce 3Cu 4As 4O 2 were examined through neutron scattering and physical properties measurements on polycrystalline samples. The lamellar structure consists of alternating layers of CeCu 4As 4 with

Modulated Magnetism and Anomalous Electronic Transport in Ce 3 Cu 4 As 4 O 2

August 29, 2016
Author(s)
Jiakui K. Wang, Shan Wu, Yiming Qiu, Jose Rodriguez Rivera, Qingzhen Huang, Collin L. Broholm, E. Morosan
The complex magnetism and transport properties of tetragonal Ce 3Cu 4As 4O 2 were examined through neutron scattering and physical properties measurements on polycrystalline samples. We find a lamellar structure consisting of alternating layers of CeCu 4As

Physical Realization of a Quantum Spin Liquid Based on a Complex Frustration Mechanism

July 25, 2016
Author(s)
Christian Balz, Bella Lake, Johannes Reuther, Hubertus Luetkens, Rico Schonemann, Thomas Herrmannsdorfer, Yogesh Singh, A.T.M. Nazmul Islam, Elisa M. Wheeler, Jose Rodriguez Rivera, Tatiana Guidi, G. Giovanna Simeoni, Chris Baines, Hanjo Ryll
Unlike conventional magnets where the magnetic moments are partially or completely static in the ground state, in a quantum spin liquid they remain in collective motion down to the lowest temperatures. The importance of this stat is that it is coherent and

Single to Multiquasiparticle Excitations in the Itinerant Helical Magnet CeRhIn 5

June 19, 2015
Author(s)
C. Stock, Jose Rodriguez Rivera, Karin Schmalzl, E. E. Rodriguez, A. Stunault, C. Petrovic
CeRhIn 5 is an itinerant magnet where the Ce 3+ spins order in a simple spiral phase caused by competing exchange interactions. We investigate the spin excitations and observe sharp spin- waves parameterized by a nearest neighbor exchange J RKKY =0.88 ±0

Disorder from Order Among Anisotropic Next-Nearest-Neighbor Ising Spin Chains in SrHo 2 O 4

February 26, 2015
Author(s)
J.-J. Wen, W. Tian, V. O. Garlea, S. M. Koohpayeh, T. M. McQueen, H.-F. Li, J.-Q. Yan, Jose Rodriguez Rivera, D. Vaknin, Collin L. Broholm
We describe why Ising spin chains with competing interactions in SrHo 2O 4 segregate into ordered and disordered ensembles at low temperatures (T). Using elastic neutron scattering, magnetization, and specific heat measurements, the two distinct spin

Low-Energy Phonons and Superconductivity in Sn 0.8In d0.2^Te

February 26, 2015
Author(s)
Zhijun Xu, J. A. Schneeloch, Ruidan Zhong, Jose Rodriguez Rivera, Leland Harriger, R. J. Birgeneau, Genda Gu, J. M. Tranquada, Guangyong Xu
We present neutron scattering measurements on low energy phonons from a superconducting (T c 2.7 K) Sn 0.8In 0.2Te Single crystal sample. The longitudinal and a transverse acoustic phonon modes have been mapped out around the (002) Bragg peak for

Short-Range Correlations in the Magnetic Ground State of Na 4 Ir 3 O 8

December 12, 2014
Author(s)
Rebecca Dally, Tom Hogan, Alex Amato, Chris Baines, Jose Rodriguez Rivera, Michael J. Graf, Stephen D. Wilson
The magnetic ground state of the J eff = 1/2 hyper-Kagome lattice in Na 4Ir 3O 8 is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen, state comprised of quasi-static moments develops

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