Classical Spin Glass Research Articles

Very low field susceptibility of the highly frustrated CsMnFeF6 and CsNiFeF6 compounds

Low field ac and dc susceptibility measurements of the highly frustrated compounds CsNiFeF6 and CsMnFeF6 reveal fundamental differences with the classical spin glass behaviour, and do not allow to conclude on the low temperature state of these compounds.

Collective excitations in a planar model of a classical spin glass

The authors have extended earlier numerical investigations of the harmonic collective excitations in the Edwards-Anderson model (1976) of a planar spin glass to one and two dimensions. In two dimensions, as in three, low-frequency excitations propagate modes with a linear dispersion law. They outline a theoretical analysis based on the coherent potential approximation (CPA) which reproduces the spin-wave velocities that were inferred from the numerical work. In one dimension the CPA accounts for the density of states and the dynamic structure factor over the entire zone except possibly at very long wavelengths where a non-linear dispersion law is predicted.

Magnetic properties of an amorphous insulating spin glass: manganese aluminosilicate

The authors report on susceptibility and magnetisation measurements of amorphous manganese aluminosilicate and demonstrate that they can be considered as insulating spin glasses with large antiferromagnetic interactions. In particular, the cusp of chi (T) at Tf is easily rounded under weak static magnetic fields. The in-field magnetisation curves for H<5 kOe and the field and time dependence of the remanent magnetisation have a similar behaviour to classical metallic spin glass alloys. The spin freezing temperature Tf depends weakly on the frequency used in susceptibility measurements and this cannot be understood on the basis of the small magnetic particle model.

Propagating modes in a three-dimensional planar model of a classical spin glass

Numerical techniques have been used to study the collective excitations in a three-dimensional planar model of a classical spin glass. The ground-state energy, density of states, static susceptibility and dynamic structure factors were calculated for 6*6*6 and 8*8*8 arrays. At long wavelengths the response was dominated by propagating modes. It was found that the energy of the propagating modes was proportional to the wavevector while the linewidth was proportional to k2. The results are in qualitative agreement with the predictions of the theory of Edwards and Anderson (1976).

Abstract: Numerical studies of the low temperature behavior of a three dimensional planar model of a classical spin glass

Calculations of the ground state properties and low lying excitations in a three dimensional planar model of a classical spin glass are presented. (AIP)

Spin diffusion in a Heisenberg spin glass

Using a combination of analytic and Monte Carlo techniques we obtain estimates for the spin diffusion constant and spin conductivity in a classical simple cubic Heisenberg spin glass which has a Gaussian distribution of exchange interactions between nearest neighbors.

Computer simulation of spin glasses and mictomagnets

Abstract Simulation on finite samples of 200, and 1000 spins suggests that the ground state of a classical spin glass is basically a random 3D spin structure but with slight ferromagnetic alignment. The internal field distribution gives a T 3 specific heat term. Spin correlation functions for mictomagnets are also obtained.

Monte Carlo studies of the internal energy and specific heat of a classical Heisenberg spin glass

We present data obtained from Monte Carlo studies of the Edwards-Anderson model of a classical Heisenberg spin glass. The internal energy is calculated for a 10 × 10 × 10 array. The specific heat, obtained from the temperature derivative of the internal energy, has a rounded peak at slightly less than one half the mean field transition temperature.