Citation

S. Itoh et al., Critical spin dynamics in the two-dimensional percolating Ising antiferromagnet, Rb2CocMg1-cF4, J PHYS JPN, 70(10), 2001, pp. 3107-3111

Citations number

23

Language

INGLESE

art.tipo

Article

Categorie Soggetti

Physics

Journal title

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN

ISSN journal

0031-9015
→ ACNP

Volume

70

Issue

10

Year of publication

2001

Pages

3107 - 3111

Database

ISI

SICI code

0031-9015(200110)70:10<3107:CSDITT>2.0.ZU;2-V

Abstract

We performed inelastic neutron-scattering experiments with high energy reso
lution, in order to investigate the critical spin dynamics in the two-dimen
sional (2D) Ising antiferromagnet, Rb2CoeMg1-cF4, with c = 0.6, 0.65, 0.7 a
nd 1, above the percolation threshold c(p) (c(p) = 0.593 for a square latti
ce). First, we have confirmed the dynamical scaling for the homogeneous sys
tem (c = 1), and the observed dynamical critical exponent (z = 2.01 +/- 0.0
5) was very close to that obtained from recent numerical studies. Next, the
observed spin dynamics in the dilute systems could be described by the tem
perature dependence expected by the standard scaling theory, the power of t
he, reduced temperature, however, the values of the exponents deviate from
those predicted by the 2D Ising model and increase as c approaches to c, fr
om the homogeneous limit. Also, the observed spin dynamics for c close cp w
as in a quantitatively good agreement with that predicted by the model for
critical spin dynamics in a percolating Ising system, in which the nature o
f the spin dynamics is determined by the requirement to overcome, via therm
al excitation, energy barriers to the overturning of the spins in domains r
esulting from the inhomogeneous geometry of the percolating network. Althou
gh we could not directly detect the difference in the functional form betwe
en that expected by the standard scaling theory and that predicted by the p
ercolation model in the present experimental condition, we conclude, from t
he quantitative agreement, that the critical spin dynamics in Rb2CoeMg1-eF4
with e close to and just above c(p) is well described by the percolation m
odel.