skip to main content


This content will become publicly available on February 14, 2019

Title: La 139 NMR investigation of the charge and spin order in a La 1.885 Sr 0.115 CuO 4 single crystal

139La NMR is suited for investigations into magnetic properties of La 2CuO 4 -based cuprates in the vicinity of their magnetic instabilities, owing to the modest hyperfine interactions between 139La nuclear spins and Cu electron spins. We report comprehensive 139La NMR measurements on a single-crystal sample of high-T c superconductor La 1.885 Sr 0.115 CuO 4 in a broad temperature range across the charge and spin order transitions (T charge ≃ 80 K, T neutron spin ≃ T c = 30 K). From the high-precision measurements of the linewidth for the nuclear spin I z = + 1 / 2 to -1/2 central transition, we show that paramagnetic line broadening sets in precisely at T charge due to enhanced spin correlations within the CuO 2 planes. Additional paramagnetic line broadening ensues below ~35 K, signaling that Cu spins in some segments of CuO 2 planes are on the verge of three-dimensional magnetic order. A static hyperfine magnetic field arising from ordered Cu moments along the ab plane, however, begins to develop only below T$$μSR\atop{spin}$$ = 15 – 20 K, where earlier muon spin rotation measurements detected Larmor precession for a small volume fraction (~20 % ) of the sample. Based on the measurement of 139 La nuclear-spin-lattice relaxation rate 1/T 1, we also show that charge order triggers enhancement of low-frequency Cu spin fluctuations inhomogeneously; a growing fraction of 139 La sites is affected by enhanced low-frequency spin fluctuations toward the eventual magnetic order, whereas a diminishing fraction continues to exhibit a behavior analogous to the optimally superconducting phase even below T charge. In conclusion, these 139La NMR results corroborate our recent 63Cu NMR observation that a very broad, anomalous winglike signal gradually emerges below T charge, whereas the normally behaving, narrower main peak is gradually wiped out [T. Imai et al., Phys. Rev. B 96, 224508 (2017)]. Furthermore, we show that the enhancement of low-energy spin excitations in the low-temperature regime below Tneutron spin (≃ Tc) depends strongly on the magnitude and orientation of the applied magnetic field.
 [1] ;  [1] ;  [2] ;  [3] ;  [3] ;  [4]
  1. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy
  2. McMaster Univ., Hamilton, ON (Canada). Dept. of Physics and Astronomy; Canadian Inst. for Advanced Research, Toronto, ON (Canada)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES); Stanford Univ., CA (United States). Dept. of Applied Physics
  4. Tohoku Univ., Sendai (Japan). Inst. for Materials Research
Publication Date:
Grant/Contract Number:
AC02-76SF00515; 16H02125
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 6; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Grant-in-Aid for Scientific Research, Japan
Country of Publication:
United States
OSTI Identifier: