Néel temperature for quasi-two-dimensional dipolar antiferromagnets.

Abstract

We calculate the N\'eel temperature ${\mathit{T}}_{\mathit{N}}$ for two-dimensional isotropic dipolar Heisenberg antiferromagnets via linear spin-wave theory and a high-temperature expansion, by employing the method of Callen. The theoretical predictions for ${\mathit{T}}_{\mathit{N}}$ for ${\mathrm{K}}_{2}$${\mathrm{MnF}}_{4}$, ${\mathrm{Rb}}_{2}$${\mathrm{MnF}}_{4}$, ${\mathrm{Rb}}_{2}$${\mathrm{MnCl}}_{4}$, and (${\mathrm{CH}}_{3}$${\mathrm{NH}}_{3}$${)}_{2}$${\mathrm{MnCl}}_{4}$ are in good agreement with the measured values.