skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Gapped excitations in the high-pressure antiferromagnetic phase of URu 2 Si 2

Abstract

Here, we report a neutron scattering study of the magnetic excitation spectrum in each of the three temperature and pressure driven phases of URu 2Si 2. We also found qualitatively similar excitations throughout the (H0L) scattering plane in the hidden order and large moment phases, with no changes in the hbar-omega-widths of the excitations at the Sigma = (1.407,0,0) and Z = (1,0,0) points, within our experimental resolution. There is, however, an increase in the gap at the Sigma point and an increase in the first moment of both excitations. At 8 meV where the Q-dependence of magnetic scattering in the hidden order phase is extended in Q-space, the excitations in the large moment phase are sharper. Furthermore, the expanded Q-hbar-omega coverage of this study suggest more complete nesting within the antiferromagnetic phase, an important property for future theoretical predictions of a hidden order parameter.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [5];  [7];  [8];  [9];  [4];  [9];  [3];  [10]
  1. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy
  2. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
  3. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter and Dept. of Physics and Astronomy
  4. National Research Council, Chalk River, ON (Canada)
  5. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  6. (United States). Dept. of Materials Science and Engineering
  7. McMaster Univ., Hamilton, ON (Canada). Brockhouse Inst. for Materials Science
  8. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy and Brockhouse Inst. for Materials Science
  9. (Canada)
  10. (NIST), Gaithersburg, MD (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1361303
Alternate Identifier(s):
OSTI ID: 1360996
Grant/Contract Number:
AC05-00OR22725; FG02-08ER46544
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 19; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Williams, Travis J., Oak Ridge National Lab., Barath, Harini, Yamani, Zahra, Rodriguez-Riviera, Jose A., Univ. of Maryland, College Park, MD, Leão, Juscelino B., Garrett, Jim D., Luke, Garrett M., Canadian Inst. for Advanced Research, Toronto, ON, Buyers, W. J. L., Canadian Inst for Advanced Research, Toronto, ON, Broholm, C., and National Inst. of Standards and Technology. Gapped excitations in the high-pressure antiferromagnetic phase of URu2Si2. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.195171.
Williams, Travis J., Oak Ridge National Lab., Barath, Harini, Yamani, Zahra, Rodriguez-Riviera, Jose A., Univ. of Maryland, College Park, MD, Leão, Juscelino B., Garrett, Jim D., Luke, Garrett M., Canadian Inst. for Advanced Research, Toronto, ON, Buyers, W. J. L., Canadian Inst for Advanced Research, Toronto, ON, Broholm, C., & National Inst. of Standards and Technology. Gapped excitations in the high-pressure antiferromagnetic phase of URu2Si2. United States. doi:10.1103/PhysRevB.95.195171.
Williams, Travis J., Oak Ridge National Lab., Barath, Harini, Yamani, Zahra, Rodriguez-Riviera, Jose A., Univ. of Maryland, College Park, MD, Leão, Juscelino B., Garrett, Jim D., Luke, Garrett M., Canadian Inst. for Advanced Research, Toronto, ON, Buyers, W. J. L., Canadian Inst for Advanced Research, Toronto, ON, Broholm, C., and National Inst. of Standards and Technology. Wed . "Gapped excitations in the high-pressure antiferromagnetic phase of URu2Si2". United States. doi:10.1103/PhysRevB.95.195171.
@article{osti_1361303,
title = {Gapped excitations in the high-pressure antiferromagnetic phase of URu2Si2},
author = {Williams, Travis J. and Oak Ridge National Lab. and Barath, Harini and Yamani, Zahra and Rodriguez-Riviera, Jose A. and Univ. of Maryland, College Park, MD and Leão, Juscelino B. and Garrett, Jim D. and Luke, Garrett M. and Canadian Inst. for Advanced Research, Toronto, ON and Buyers, W. J. L. and Canadian Inst for Advanced Research, Toronto, ON and Broholm, C. and National Inst. of Standards and Technology},
abstractNote = {Here, we report a neutron scattering study of the magnetic excitation spectrum in each of the three temperature and pressure driven phases of URu2Si2. We also found qualitatively similar excitations throughout the (H0L) scattering plane in the hidden order and large moment phases, with no changes in the hbar-omega-widths of the excitations at the Sigma = (1.407,0,0) and Z = (1,0,0) points, within our experimental resolution. There is, however, an increase in the gap at the Sigma point and an increase in the first moment of both excitations. At 8 meV where the Q-dependence of magnetic scattering in the hidden order phase is extended in Q-space, the excitations in the large moment phase are sharper. Furthermore, the expanded Q-hbar-omega coverage of this study suggest more complete nesting within the antiferromagnetic phase, an important property for future theoretical predictions of a hidden order parameter.},
doi = {10.1103/PhysRevB.95.195171},
journal = {Physical Review B},
number = 19,
volume = 95,
place = {United States},
year = {Wed May 31 00:00:00 EDT 2017},
month = {Wed May 31 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on May 31, 2018
Publisher's Version of Record

Save / Share:
  • Cited by 3
  • Inmore » this paper, we report inelastic neutron scattering measurements of the magnetic excitations of green dioptase Cu 6[Si 6O 18]∙6H 2O. The observed spectrum contains two magnetic modes and a prominent spin gap that is consistent with the ordered ground state of Cu moments coupled antiferromagnetically in spiral chains along the c axis and ferromagnetically in ab planes on the hexagonal cell. The data are in excellent agreement with a spin- 1 2 Hamiltonian that includes antiferromagnetic nearest-neighbor intrachain coupling J c=10.6(1) meV, ferromagnetic interchain coupling J ab=₋1.2 (1) meV, and exchange anisotropy ΔJ c=0.14(1) meV. We calculated the sublattice magnetization to be strongly reduced, ~0.39μ B. This appears compatible with a reduced Néel temperature, T N=14.5K<c, and can be explained by a presence of quantum spin fluctuations« less
  • Cited by 4
  • Measurements of electrical resistivity, ρ(T ), were performed under quasihydrostatic pressure up to P ~ 2.2 GPa to determine the pressure dependence of the so-called hidden order (HO) and large-moment antiferromagnetic (LMAFM) phases for the URu 2-xFexSi2 system with x = 0.025, 0.05, 0.10, 0.15, and 0.20. As the Fe concentration (x) is increased, we observed that a smaller amount of external pressure, P c, is required to induce the HO → LMAFM phase transition. A critical pressure of P c ~ 1.2 GPa at x = 0.025 reduces to P c ~ 0 at x = 0.15, suggesting themore » URu 2-xFe xSi 2 system is fully expressed in the LMAFM phase for x ≥ x* c = 0.15, where x * c denotes the ambient pressure critical concentration of Fe. Furthermore, when using a bulk modulus calculation to convert x to chemical pressure, P ch(x), we consistently found that the induced HO → LMAFM phase transition occurred at various combinations of x c and P c such that P ch(x c) + P c ≈ 1.5 GPa, where xc denotes those critical concentrations of Fe that induce the HO→LMAFM phase transition for the URu 2-xFe xSi 2 compounds under pressure. We performed exponential fits of ρ(T ) in the HO and LMAFM phases in order to determine the pressure dependence of the energy gap, , that opens over part of the Fermi surface in the transition from the paramagnetic (PM) phase to the HO/LMAFM phase at the transition temperature, T 0. Finally, this change in the pressure variation of Δ(P) at the HO→LMAFM phase transition is consistent with the values of P c determined from the T 0(P) phase lines at the PM→HO/LMAFM transition.« less