skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on September 13, 2018

Title: Quasi-two-dimensional spin correlations in the triangular lattice bilayer spin glass LuCoGaO 4

Here we present a single-crystal time-of-flight neutron scattering study of the static and dynamic spin correlations in LuCoGaO 4, a quasi-two-dimensional dilute triangular lattice antiferromagnetic spin-glass material. This system is based on Co 2+ ions that are randomly distributed on triangular bilayers within the YbFe 2O 4 type, hexagonal crystal structure. Antiferromagnetic short-range two-dimensional correlations at wave vectors Q = (1/3,1/3, L) develop within the bilayers at temperatures as high as |Θ CW| ~100 K and extend over roughly five unit cells at temperatures below T g = 19 K. These two-dimensional static correlations are observed as diffuse rods of neutron scattering intensity along c * and display a continuous spin freezing process in their energy dependence. Aside from exhibiting these typical spin-glass characteristics, this insulating material reveals a novel gapped magnetic resonant spin excitation at ΔE ~12 meV localized around Q = (1 / 3, 1 / 3,L) . The temperature dependence of the spin gap associated with this two-dimensional excitation correlates with the evolution of the static correlations into the spin-glass state ground state. Lastly, we associate it with the effect of the staggered exchange field acting on the S eff = 1/2 Ising-like doublet of the Comore » 2+ moments.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [5] ;  [6] ;  [7]
  1. Helmholtz-Zentrum Berlin (HZB), (Germany). German Research Centre for Materials and Energy; McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy
  2. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Colorado State Univ., Fort Collins, CO (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Data Analysis and Visualization Division
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
  5. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Stanford Univ., CA (United States)
  6. rockhouse Inst. for Materials Research, Hamilton, ON (Canada)
  7. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Brockhouse Inst. for Materials Research, Hamilton, ON (Canada); Canadian Inst. for Advanced Research, Toronto, ON (Canada)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 9; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC); Natural Sciences and Engineering Research Council of Canada (NSERC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1399429
Alternate Identifier(s):
OSTI ID: 1389899