Monte Carlo simulations of the kagome lattice with magnetic dipolar interactions

TL;DR

This paper presents extensive Monte Carlo simulations of classical spins on a kagome lattice with dipolar interactions, revealing ground state degeneracy, phase transition nature, and the role of competing interactions and fluctuations in ordering.

Contribution

It provides new insights into the finite-temperature behavior and ground state degeneracy of dipolar-interacting spins on the kagome lattice, highlighting the effects of competing interactions.

Findings

Identification of six-fold degenerate ground state.

Characterization of the finite-temperature phase transition.

Observation of persistent fluctuations into the ordered state.

Abstract

The results of extensive Monte Carlo simulations of classical spins on the two-dimensional kagome lattice with only dipolar interactions are presented. In addition to revealing the six-fold degenerate ground state, the nature of the finite-temperature phase transition to long-range magnetic order is discussed. Low temperature states consisting of mixtures of degenerate ground state configurations separated by domain walls can be explained as a result of competing exchange-like and shape anisotropy-like terms in the dipolar coupling. Fluctuations between pairs of degenerate spin configurations are found to persist well into the ordered state as the temperature is lowered until locking in to a low-energy state.