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Title: Muon spin relaxation study of spin dynamics in the extended kagome systems YBaCo 4 O 7 + δ   ( δ = 0 , 0.1 )

Here, we present muon spin relaxation (μSR) measurements of the extended kagome systems YBaCo 4O 7+δ (δ = 0,0.1), comprising two interpenetrating kagome sublattice of Co(I) 3+ (S = 3/2) and a triangle sublattice of Co(II) 2+ (S = 2). The zero- and longitudinal-field μ SR spectra of the stoichiometric compound YBaCo 4O 7 unveil that the triangular subsystem orders at TN = 101 K. In contrast, the muon spin relaxation rate pertaining to the kagome subsystem shows persistent spin dynamics down to T = 20 K and then a sublinear decrease λ(T ) ~ T 0.66(5) on cooling towards T = 4 K. In addition, the introduction of interstitial oxygen (δ = 0.1) is found to drastically affect the magnetism. For the fast-cooling experiment (>10 K/min), YBaCo 4O 7.1 enters a regime characterized by persistent spin dynamics below 90 K. For the slow-cooling experiment (1 K/min), evidence is obtained for the phase separation into interstitial oxygen-poor and oxygen-rich regions with distinct correlation times. The observed temperature, cooling rate, and oxygen content dependencies of spin dynamics are discussed in terms of a broad range of spin-spin correlation times, relying on a different degree of frustration between the kagome and trianglemore » sublattices as well as of oxygen migration.« less
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [3] ;  [1]
  1. Chung-Ang Univ., Seoul (Korea, Republic of). Dept. of Physics
  2. Catholic Univ of Korea, Bucheon (Korea, Republic of). Dept. of Physics
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357; 2009-0093817; 20170211; 20170065
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 10; 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); Korea Research Foundation (KRF)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1433055

Lee, S., Lee, Wonjun, Lee, K. J., Kim, ByungJun, Suh, B. J., Zheng, H., Mitchell, J. F., and Choi, K. -Y.. Muon spin relaxation study of spin dynamics in the extended kagome systems YBaCo4O7+δ (δ=0,0.1). United States: N. p., Web. doi:10.1103/PhysRevB.97.104409.
Lee, S., Lee, Wonjun, Lee, K. J., Kim, ByungJun, Suh, B. J., Zheng, H., Mitchell, J. F., & Choi, K. -Y.. Muon spin relaxation study of spin dynamics in the extended kagome systems YBaCo4O7+δ (δ=0,0.1). United States. doi:10.1103/PhysRevB.97.104409.
Lee, S., Lee, Wonjun, Lee, K. J., Kim, ByungJun, Suh, B. J., Zheng, H., Mitchell, J. F., and Choi, K. -Y.. 2018. "Muon spin relaxation study of spin dynamics in the extended kagome systems YBaCo4O7+δ (δ=0,0.1)". United States. doi:10.1103/PhysRevB.97.104409.
@article{osti_1433055,
title = {Muon spin relaxation study of spin dynamics in the extended kagome systems YBaCo4O7+δ (δ=0,0.1)},
author = {Lee, S. and Lee, Wonjun and Lee, K. J. and Kim, ByungJun and Suh, B. J. and Zheng, H. and Mitchell, J. F. and Choi, K. -Y.},
abstractNote = {Here, we present muon spin relaxation (μSR) measurements of the extended kagome systems YBaCo4O7+δ (δ = 0,0.1), comprising two interpenetrating kagome sublattice of Co(I)3+ (S = 3/2) and a triangle sublattice of Co(II)2+ (S = 2). The zero- and longitudinal-field μ SR spectra of the stoichiometric compound YBaCo4O7 unveil that the triangular subsystem orders at TN = 101 K. In contrast, the muon spin relaxation rate pertaining to the kagome subsystem shows persistent spin dynamics down to T = 20 K and then a sublinear decrease λ(T ) ~ T0.66(5) on cooling towards T = 4 K. In addition, the introduction of interstitial oxygen (δ = 0.1) is found to drastically affect the magnetism. For the fast-cooling experiment (>10 K/min), YBaCo4O7.1 enters a regime characterized by persistent spin dynamics below 90 K. For the slow-cooling experiment (1 K/min), evidence is obtained for the phase separation into interstitial oxygen-poor and oxygen-rich regions with distinct correlation times. The observed temperature, cooling rate, and oxygen content dependencies of spin dynamics are discussed in terms of a broad range of spin-spin correlation times, relying on a different degree of frustration between the kagome and triangle sublattices as well as of oxygen migration.},
doi = {10.1103/PhysRevB.97.104409},
journal = {Physical Review B},
number = 10,
volume = 97,
place = {United States},
year = {2018},
month = {3}
}