Anomalous Spin Diffusion in Classical Heisenberg Magnets

Authors

Gerhard Müller, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

6-27-1988

Abstract

Time-dependent spin-autocorrelation functions at T = ∞ for classical Heisenberg magnets in dimensionalities d = 1, 2., and 3 are investigated by means of a computer simulation. These functions are shown to exhibit power-law long-time tails of form t^-a_d with characteristic exponents α_d which differ significantly from the values α_d^(SD) = d/2 predicted by the phenomenological spin-diffusion theory: α₁ = 0.609 ± 0.005, α₂ = 1.050 ± 0.025, α₃≃1.6. The method to employ computer simulations for this problem differs from methods previously employed. Anomalous spin diffusion is confirmed by existing proton spin-lattice relaxation data for the quasi-1D s = 5/2 Heisenberg antiferromagnet (CH₃)₄ NMnCl₃.

Citation/Publisher Attribution

Gerhard Müller. Anomalous spin diffusion in classical Heisenberg magnets. Phys. Rev. Lett. 60 (1988), 2785-2788; 63 (1989), 813.

Available at: http://dx.doi.org/10.1103/PhysRevLett.60.2785

Publisher Statement

© 1988 The American Physical Society