Thermodynamics of a two-dimensional Heisenberg ferromagnet with dipolar interaction

X iv : c on d - m at / 9 60 41 90 v 1 1 M ay 1 99 6 Circular phase of a two dimensional ferromagnet with dipolar interactions

We make for the first time a large-scale Monte-Carlo simulation of a fer-romagnetic Heisenberg model with dipolar interactions on a two dimensional square lattice with open boundaries using an efficient new technique. We find that a phase transition occurs in the model and the ordered phase is characterized by a circular arrangement of the spins.

Thermodynamic properties of a classical d-dimensional spin-S Heisenberg ferromagnet with long-range interactions via the spectral density method

The thermodynamic properties of a classical d-dimensional spin-S Heisenberg ferromagnet, with long-range interactions decaying as r−p and in the presence of an external magnetic field, is investigated by means of the spectral density method in the framework of classical statistical mechanics. We find that long-range order exists at finite temperature for d < p < 2d with d ≤ 2 and for p > d with...

Effect of a Field on the Thermodynamics of the Randomly Dilute 1d Heisenberg Ferromagnet

Se p 20 01 Evaluation of Integrals Representing Correlations in XXX Heisenberg Spin Chain

We study XXX Heisenberg spin 1/2 anti-ferromagnet. We evaluate a probability of formation of a ferromagnetic string in the anti-ferromagnetic ground state in thermodynamics limit. We prove that for short strings the probability can be expressed in terms of Riemann zeta function with odd arguments.

IC/2001/106 United Nations Educational Scientific and Cultural organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS DIPOLAR EFFECTS ON SOLITON DYNAMICS ON A DISCRETE FERROMAGNETIC CHAIN

Contributions of dipole-dipole interactions to the dynamics of solitons and specific heat on a one-dimensional (ID) discrete easy-plane Heisenberg ferromagnet in which the biquadratic exchange interactions are taken into account in addition to the Zeeman energy, the uniaxial anisotropy and the exchange energy are studied numerically. Results of a numerical simulation of the dynamics of a single...