Order-by-disorder effects in antiferromagnets on face-centered cubic lattice

Abstract

We discuss the role of quantum fluctuations in Heisenberg antiferromagnets on face-centered cubic lattice with small dipolar interaction in which the next-nearest-neighbor exchange coupling dominates over the nearest-neighbor one. It is well known that a collinear magnetic structure which contains (111) ferromagnetic planes arranged antiferromagnetically along one of the space diagonals of the cube is stabilized in this model via order-by-disorder mechanism. On the mean-field level, the dipolar interaction forces spins to lie within (111) planes. By considering 1/S - corrections to the ground state energy, we demonstrate that quantum fluctuations lead to an anisotropy within (111) planes favoring three equivalent directions for the staggered magnetization (e.g., $[11\overline{2}]$, $[1\overline{2}1]$, and $[\overline{2}11]$ directions for (111) plane). Such in-plane anisotropy was obtained experimentally in related materials MnO, $\alpha$-MnS, $\alpha$-MnSe, EuTe, and EuSe. We find that the order-by-disorder mechanism can contribute significantly to the value of the in-plane anisotropy in EuTe. Magnon spectrum is also derived in the first order in 1/S.

9 pages, 1 colour figures

References in corpus (5)

• Definitive Evidence for Order-by-Quantum-Disorder in Er2Ti2O7
• Renormalization of the spin-wave spectrum in three-dimentional ferromagnets with dipolar interaction
• Spin-wave interaction in two-dimensional ferromagnets with dipolar forces
• Anomalously large damping of long-wavelength quasiparticles caused by long-range interaction
• Breakdown of long-wavelength magnons in cubic antiferromagnets with dipolar forces at small temperature

Cited by in corpus (5)

• Quantum versus thermal fluctuations in the fcc antiferromagnet: alternative routes to order by disorder
• Magnon spectrum of the Weyl semimetal half-Heusler compound GdPtBi
• Ground state selection by magnon interactions in the fcc antiferromagnet
• Spin-flop transition accompanied with changing the type of magnetic ordering
• Microscopic Origin of Reduced Magnetic Order in a Frustrated Metal