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Title: Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}

Abstract

{sup 63}Cu NQR T{sub 1} and T{sub 2} relaxation measurements in La{sub 2}Cu{sub 1{minus}x}Zn{sub x}O{sub 4}, for 0{le}x{le}0.11 and in the temperature range T{sub N}{le}T{le}900 K, are presented. The results are used to derive insights into the Cu{sup 2+} correlated spin dynamics in the paramagnetic phase of the S=(1)/(2) two-dimensional (2D) Heisenberg (H) antiferromagnets (AF), and into the disorder effects associated with the spin vacancy due to Zn{sup 2+} (S=0) for Cu{sup 2+} substitution. In particular, by using scaling arguments for the static generalized susceptibility, {chi}({rvec q},0), and for the decay rate, {Gamma}{sub {rvec q}}, of the normal excitations, T{sub 2} and T{sub 1} are related to the in-plane correlation length {xi}{sub 2D}(x,T) and its dependence on temperature and Zn doping, x, is extracted. The experimental findings are analyzed in light of the quantum critical and renormalized classical behaviors for {xi}{sub 2D} predicted by recent theories for S=1/2 HAF on square lattices. It is shown that up to T{approx_equal}900 K, {xi}{sub 2D} is consistent with the assumption of a renormalized classical regime, in agreement with recent neutron scattering results and at variance with previous interpretations of the NQR data. It is discussed how Zn affects {xi}{sub 2D} through the modificationmore » in the spin stiffness and comparison with the disorder induced by itinerant extra holes is made.« less

Authors:
; ;  [1]
  1. Department of Physics A. Volta, Unita INFM and Sezione INFN di Pavia, Via Bassi, 6, 27100-I Pavia (Italy)
Publication Date:
OSTI Identifier:
450387
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 55; Journal Issue: 6; Other Information: PBD: Feb 1997
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LANTHANUM OXIDES; NUCLEAR QUADRUPOLE RESONANCE; COPPER OXIDES; HIGH-TC SUPERCONDUCTORS; SPIN-SPIN RELAXATION; MAGNETIC SUSCEPTIBILITY; LATTICE PARAMETERS; HEISENBERG MODEL; ANTIFERROMAGNETIC MATERIALS; PHASE TRANSFORMATIONS

Citation Formats

Carretta, P, Rigamonti, A, and Sala, R. Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}. United States: N. p., 1997. Web. doi:10.1103/PhysRevB.55.3734.
Carretta, P, Rigamonti, A, & Sala, R. Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}. United States. https://doi.org/10.1103/PhysRevB.55.3734
Carretta, P, Rigamonti, A, and Sala, R. Sat . "Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}". United States. https://doi.org/10.1103/PhysRevB.55.3734.
@article{osti_450387,
title = {Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}},
author = {Carretta, P and Rigamonti, A and Sala, R},
abstractNote = {{sup 63}Cu NQR T{sub 1} and T{sub 2} relaxation measurements in La{sub 2}Cu{sub 1{minus}x}Zn{sub x}O{sub 4}, for 0{le}x{le}0.11 and in the temperature range T{sub N}{le}T{le}900 K, are presented. The results are used to derive insights into the Cu{sup 2+} correlated spin dynamics in the paramagnetic phase of the S=(1)/(2) two-dimensional (2D) Heisenberg (H) antiferromagnets (AF), and into the disorder effects associated with the spin vacancy due to Zn{sup 2+} (S=0) for Cu{sup 2+} substitution. In particular, by using scaling arguments for the static generalized susceptibility, {chi}({rvec q},0), and for the decay rate, {Gamma}{sub {rvec q}}, of the normal excitations, T{sub 2} and T{sub 1} are related to the in-plane correlation length {xi}{sub 2D}(x,T) and its dependence on temperature and Zn doping, x, is extracted. The experimental findings are analyzed in light of the quantum critical and renormalized classical behaviors for {xi}{sub 2D} predicted by recent theories for S=1/2 HAF on square lattices. It is shown that up to T{approx_equal}900 K, {xi}{sub 2D} is consistent with the assumption of a renormalized classical regime, in agreement with recent neutron scattering results and at variance with previous interpretations of the NQR data. It is discussed how Zn affects {xi}{sub 2D} through the modification in the spin stiffness and comparison with the disorder induced by itinerant extra holes is made.},
doi = {10.1103/PhysRevB.55.3734},
url = {https://www.osti.gov/biblio/450387}, journal = {Physical Review, B: Condensed Matter},
number = 6,
volume = 55,
place = {United States},
year = {1997},
month = {2}
}