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Search Publications by: Nicholas Butch (Fed)

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Displaying 126 - 150 of 152

Distinct Magnetic Spectra in the Hidden Order and Antiferromagnetic Phases in URu 2-x Fe x Si 2

November 7, 2016
Author(s)
Nicholas P. Butch, Sheng Ran, Inho Jeon, Noravee Kanchanavatee, Kevin Huang, Alexander Breindel, M. Brian Maple, Ryan L. Stillwell, Yang Zhao, Leland Weldon Harriger, Jeffrey W. Lynn
We use neutron scattering to compare the magnetic excitations in the hidden order (HO) and antiferromagnetic (AFM) phases in URu 2-xFe xFe xSi 2 as a function of Fe concentration. The magnetic excitation spectra change significantly between x=0.05 and x=0

Spin-Orbit Coupled Molecular Quantum Magnetism Realized in Inorganic Solid

September 21, 2016
Author(s)
Sang-Youn Park, S.-H. Do, K.-Y. Choi, J.-H. Kang, Dongjin Jang, B. Schmidt, Manuel Brando, B.-H. Kim, D.-H. Kim, Nicholas Butch, Seongsu Lee, Sungdae Ji
The molecular magnetism, representing an isolated spin state, is of particular interest due to characteristics of quantum magnetism with quantum tunneling phenomena underlying qubits or molecular spintronics for the quantum information devices. Such

Pressure-Resistant Intermediate Valence in the Kondo Insulator SmB 6

April 15, 2016
Author(s)
Nicholas P. Butch, Johnpierre Paglione, Paul Chow, Yuming Xiao, Chris A. Marianetti, Corwin H. Booth, Jason R. Jeffries
Resonant x-ray emission spectroscopy (RXES) was used to determine the pressure dependence of the f-electron occupancy in the Kondo insulator SmB 6. Applied pressure reduces the f-occupancy, but surprisingly, the material maintains a significant divalent

Universal Dynamic Magnetism in Yb Pyrochlores with Disparate Ground States

March 14, 2016
Author(s)
A. M. Hallas, J. Gaudet, Nicholas Butch, M. Tachibana, R. S. Freitas, G. M. Lake, C. R. Wiebe, B. D. Gaulin
The ytterbium pyrochlore magnets, Yb 2B 2O 7 (B=Sn, Ti, Ge) are well described by S eff = 1/2 quantum spins with local XY anisotropy, decorating the cubic pyrochlore lattice and interacting via anisotropic exchange. Structurally, while only the non

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

Spectroscopic Determination of the Atomic f-Electron Symmetry Underlying Hidden Order in URu 2 Si 2

June 9, 2015
Author(s)
L. Andrew Wray, Jonathan Denlinger, Shih-Wen Huang, Haowei He, Nicholas Butch, M. Brian Maple, Zahid Hussain, Yi-De Chuang
The hidden order state of URu6d2^Si 2 has been a subject of intense speculation for more than 25 years, but there is still no clear consensus on what degrees of freedom are important for a low temperature physical model. Here, X-ray absorption spectroscopy

Symmetry and Correlations Underlying Hidden Order in URu 2 Si 2

January 26, 2015
Author(s)
Nicholas P. Butch, Michael E. Manley, Jason R. Jeffries, Marc Janoschek, Kevin Huang, M. Brian Maple, Ayman H. Said, Bogdan M. Leu, Jeffrey W. Lynn
The organization of correlated electrons in the Hidden Order (HO) phase of intermetallic URu 2Si 2 is a longstanding mystery. In this work, we study the symmetry by mapping the lattice and magnetic excitations via inelastic neutron and x-ray scattering

Persistent Fe Moments in the Normal-State Collapsed-Tetragonal Phase of the Pressure-induced Superconductor Ca 0.67 Sr 0.33 Fe 2 As 2

October 13, 2014
Author(s)
J.R. Jeffries, Nicholas Butch, M.J. Lipp, J.A. Bradley, K. Kirshenbaum, Shanta Saha, J. Paglione, C. Kenny-Benson, Y. Xiao, P. Chow, W. J. Evans
Using non-resonant Fe Κ}β x-ray emission spectroscopy, we reveal that Sr-doping of CaFe 2As 2 decouples the Fe moment from the volume collapse transition, yielding a collapsed-tetragonal, para-magnetic normal state out of which superconductivity develops

Robust Ferromagnetism in the Compressed Permanent Magnet Sm 2 Co 17

September 8, 2014
Author(s)
Jason R. Jeffries, L.S.I. Veiga, G. Fabbris, D. Haskel, P. Huang, Nicholas Butch, S.K. McCall, K. Holliday, Z. Jenei, Y. Xiao, P. Chow
The compound Sm 2Co 17 displays magnetic properties amenable to permanent magnet applications owing to both the 3d-electrons of Co and the 4f-electrons of Sm. The long-standing description of the magnetic interactions between the Sm and Co ions implies a

Multiple High-Temperature Transitions Driven by Dynamical Structures in NaI

June 27, 2014
Author(s)
M. E. Manley, J.R. Jeffries, H. Lee, Nicholas Butch, D. L. Abernathy
Multiple, consecutive high-temperature transitions in NaI involving dynamical order and/or localization in the energy-momentum spectrum but not in the average crystal structure are revealed by lattice dynamics, x-ray lattice spacing, and heat capacity