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Title: Random-field effects in the diluted two-dimensional Ising antiferromagnet Rb/sub 2/Co/sub 0. 7/Mg/sub 0. 3/F/sub 4/

Abstract

We report a comprehensive neutron scattering study of the spin correlations in the diluted two-dimensional (2D) Ising antiferromagnet Rb/sub 2/Co/sub 0.7/Mg/sub 0.3/F/sub 4/ in an applied magnetic field. As predicted by Fishman and Aharony, an applied field in this system produces a random staggered magnetic field. Random fields are expected to have drastic effects on the cooperative behavior of magnets although the detailed behavior remains controversial. It is found that the applied magnetic field, and by inference the concomitant random staggered fields, destroy the 2D long-range order for all temperatures and fields. The structure factor S/sup z/z(Q) = summation/sub r/e/sup i/Qxr ..T/sub N/, taking on values of about 0.7 and -1.2, respectively, at T/sub N/ = 42.5 K. For small but nonzero applied fields the inverse correlation length may be factorized into a random-field part and a thermal part, kappa = kappa/sub RF/+kappa/sub T/, with kappa/sub T/approx.ezz/k/sub B/T where J/sup z/z is the Ising exchange constant.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
OSTI Identifier:
5522409
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B: Condens. Matter; (United States)
Additional Journal Information:
Journal Volume: 28:3
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COBALT FLUORIDES; MAGNETIC PROPERTIES; MAGNESIUM FLUORIDES; RUBIDIUM FLUORIDES; ANTIFERROMAGNETIC MATERIALS; CORRELATIONS; EXPERIMENTAL DATA; ISING MODEL; MAGNETIC FIELDS; NEUTRON DIFFRACTION; PHASE TRANSFORMATIONS; RANDOMNESS; SPIN; STRUCTURE FACTORS; TEMPERATURE DEPENDENCE; VERY LOW TEMPERATURE; ALKALI METAL COMPOUNDS; ALKALINE EARTH METAL COMPOUNDS; ANGULAR MOMENTUM; COBALT COMPOUNDS; COHERENT SCATTERING; CRYSTAL MODELS; DATA; DIFFRACTION; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; INFORMATION; MAGNESIUM COMPOUNDS; MAGNETIC MATERIALS; MATERIALS; MATHEMATICAL MODELS; NUMERICAL DATA; PARTICLE PROPERTIES; PHYSICAL PROPERTIES; RUBIDIUM COMPOUNDS; SCATTERING; TRANSITION ELEMENT COMPOUNDS; 360603* - Materials- Properties

Citation Formats

Birgeneau, R J, Yoshizawa, H, Cowley, R A, Shirane, G, and Ikeda, H. Random-field effects in the diluted two-dimensional Ising antiferromagnet Rb/sub 2/Co/sub 0. 7/Mg/sub 0. 3/F/sub 4/. United States: N. p., 1983. Web. doi:10.1103/PhysRevB.28.1438.
Birgeneau, R J, Yoshizawa, H, Cowley, R A, Shirane, G, & Ikeda, H. Random-field effects in the diluted two-dimensional Ising antiferromagnet Rb/sub 2/Co/sub 0. 7/Mg/sub 0. 3/F/sub 4/. United States. https://doi.org/10.1103/PhysRevB.28.1438
Birgeneau, R J, Yoshizawa, H, Cowley, R A, Shirane, G, and Ikeda, H. 1983. "Random-field effects in the diluted two-dimensional Ising antiferromagnet Rb/sub 2/Co/sub 0. 7/Mg/sub 0. 3/F/sub 4/". United States. https://doi.org/10.1103/PhysRevB.28.1438.
@article{osti_5522409,
title = {Random-field effects in the diluted two-dimensional Ising antiferromagnet Rb/sub 2/Co/sub 0. 7/Mg/sub 0. 3/F/sub 4/},
author = {Birgeneau, R J and Yoshizawa, H and Cowley, R A and Shirane, G and Ikeda, H},
abstractNote = {We report a comprehensive neutron scattering study of the spin correlations in the diluted two-dimensional (2D) Ising antiferromagnet Rb/sub 2/Co/sub 0.7/Mg/sub 0.3/F/sub 4/ in an applied magnetic field. As predicted by Fishman and Aharony, an applied field in this system produces a random staggered magnetic field. Random fields are expected to have drastic effects on the cooperative behavior of magnets although the detailed behavior remains controversial. It is found that the applied magnetic field, and by inference the concomitant random staggered fields, destroy the 2D long-range order for all temperatures and fields. The structure factor S/sup z/z(Q) = summation/sub r/e/sup i/Qxr ..T/sub N/, taking on values of about 0.7 and -1.2, respectively, at T/sub N/ = 42.5 K. For small but nonzero applied fields the inverse correlation length may be factorized into a random-field part and a thermal part, kappa = kappa/sub RF/+kappa/sub T/, with kappa/sub T/approx.ezz/k/sub B/T where J/sup z/z is the Ising exchange constant.},
doi = {10.1103/PhysRevB.28.1438},
url = {https://www.osti.gov/biblio/5522409}, journal = {Phys. Rev. B: Condens. Matter; (United States)},
number = ,
volume = 28:3,
place = {United States},
year = {1983},
month = {8}
}