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Title: X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations

We have investigated the structural, electronic, and magnetic properties of the pyrochlore iridates Eu 2Ir 2O 7 and Pr 2Ir 2O 7 using a combination of resonant elastic x-ray scattering, x-ray powder diffraction, and resonant inelastic x-ray scattering (RIXS). The structural parameters of Eu 2Ir 2O 7 have been examined as a function of temperature and applied pressure, with a particular emphasis on regions of the phase diagram where electronic and magnetic phase transitions have been reported. We find no evidence of crystal symmetry change over the range of temperatures (~6 to 300 K) and pressures (~0.1 to 17 GPa) studied. We have also investigated the electronic and magnetic excitations in single-crystal samples of Eu 2Ir 2O 7 and Pr 2Ir 2O 7 using high-resolution Ir L- 3-edge RIXS. In spite of very different ground state properties, we find that these materials exhibit qualitatively similar excitation spectra, with crystal field excitations at ~3-5 eV, spin-orbit excitations at ~ 0.5-1 eV, and broad low-lying excitations below ~0.15 eV. In single-crystal samples of "Eu-rich" Eu 2Ir 2O 7 (found to possess an actual stoichiometry of Eu 2.18Ir 1.82O 7.06) we observe highly damped magnetic excitations at ~45 meV, which display significant momentummore » dependence. Here, we compare these results with recent dynamical structure factor calculations« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [1] ;  [1] ;  [1]
  1. Univ. of Toronto, Toronto, ON (Canada)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Seoul National Univ., Seoul (Korea, Republic of)
  4. Univ. of Ottawa, Ottawa, ON (Canada)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Canada Foundation for Innovation (CFI)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1339452

Clancy, J. P., Gretarsson, H., Lee, E. K. H., Tian, Di, Kim, J., Upton, M. H., Casa, D., Gog, T., Islam, Z., Jeon, Byung -Gu, Kim, Kee Hoon, Desgreniers, S., Kim, Yong Baek, Julian, S. J., and Kim, Young -June. X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations. United States: N. p., Web. doi:10.1103/PhysRevB.94.024408.
Clancy, J. P., Gretarsson, H., Lee, E. K. H., Tian, Di, Kim, J., Upton, M. H., Casa, D., Gog, T., Islam, Z., Jeon, Byung -Gu, Kim, Kee Hoon, Desgreniers, S., Kim, Yong Baek, Julian, S. J., & Kim, Young -June. X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations. United States. doi:10.1103/PhysRevB.94.024408.
Clancy, J. P., Gretarsson, H., Lee, E. K. H., Tian, Di, Kim, J., Upton, M. H., Casa, D., Gog, T., Islam, Z., Jeon, Byung -Gu, Kim, Kee Hoon, Desgreniers, S., Kim, Yong Baek, Julian, S. J., and Kim, Young -June. 2016. "X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations". United States. doi:10.1103/PhysRevB.94.024408. https://www.osti.gov/servlets/purl/1339452.
@article{osti_1339452,
title = {X-ray scattering study of pyrochlore iridates: Crystal structure, electronic, and magnetic excitations},
author = {Clancy, J. P. and Gretarsson, H. and Lee, E. K. H. and Tian, Di and Kim, J. and Upton, M. H. and Casa, D. and Gog, T. and Islam, Z. and Jeon, Byung -Gu and Kim, Kee Hoon and Desgreniers, S. and Kim, Yong Baek and Julian, S. J. and Kim, Young -June},
abstractNote = {We have investigated the structural, electronic, and magnetic properties of the pyrochlore iridates Eu2Ir2O7 and Pr2Ir2O7 using a combination of resonant elastic x-ray scattering, x-ray powder diffraction, and resonant inelastic x-ray scattering (RIXS). The structural parameters of Eu2Ir2O7 have been examined as a function of temperature and applied pressure, with a particular emphasis on regions of the phase diagram where electronic and magnetic phase transitions have been reported. We find no evidence of crystal symmetry change over the range of temperatures (~6 to 300 K) and pressures (~0.1 to 17 GPa) studied. We have also investigated the electronic and magnetic excitations in single-crystal samples of Eu2Ir2O7 and Pr2Ir2O7 using high-resolution Ir L-3-edge RIXS. In spite of very different ground state properties, we find that these materials exhibit qualitatively similar excitation spectra, with crystal field excitations at ~3-5 eV, spin-orbit excitations at ~ 0.5-1 eV, and broad low-lying excitations below ~0.15 eV. In single-crystal samples of "Eu-rich" Eu2Ir2O7 (found to possess an actual stoichiometry of Eu2.18Ir1.82O7.06) we observe highly damped magnetic excitations at ~45 meV, which display significant momentum dependence. Here, we compare these results with recent dynamical structure factor calculations},
doi = {10.1103/PhysRevB.94.024408},
journal = {Physical Review B},
number = 2,
volume = 94,
place = {United States},
year = {2016},
month = {7}
}

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