Triangular Antiferromagnets

TL;DR

This review discusses how magnetic frustration in stacked triangular lattices leads to complex ground states, unique phase diagrams, and diverse magnetic behaviors across various Hamiltonians, highlighting theory-experiment comparisons.

Contribution

It provides a comprehensive overview of the effects of magnetic frustration in triangular antiferromagnets, including different Hamiltonians and lattice distortions, with insights into their phase diagrams and critical phenomena.

Findings

Frustration increases ground state degeneracy.

Different Hamiltonians lead to distinct magnetic properties.

Lattice distortions and stacking types affect magnetic behavior.

Abstract

In this article we review the effects of magnetic frustation in the stacked triangular lattice. Frustration increases the degeneracy of the ground state, giving rise to different physics. In particular it leads to unique phase diagrams with multicritical points and novel critical phenomena. We describe the confrontation of theory and experiment for a number of systems with differing magnetic Hamiltonians; Heisenberg, Heisenberg with easy-axis anisotropy, Heisenberg with easy-plane anisotropy, Ising and singlet ground state. Interestingly each leads to different magnetic properties and phase diagrams. We also describe the effects of ferromagnetic, rather than antiferromagnetic, stacking and of small distortions of the triangular lattice.