Magnetic ordering in two-dimensional Heisenberg antiferromagnets with variable interlayer distances

Abstract

We have investigated the finite temperature magnetic ordering in the quasi-two-dimensional Heisenberg antiferromagnetic system $({\mathrm{C}}_{n}{\mathrm{H}}_{2n+1}{\mathrm{NH}}_{3}{)}_{2}{\mathrm{MnCl}}_{4}$ with various chain lengths n. Our results indicate that in long-chain compounds with large interlayer distances, secondary interactions in magnitude besides the exchange interaction, such as the Ising anisotropy and the Dzyaloshinsky-Moriya interaction, play an important role in the magnetic phase transitions.