Conférence du vendredi 13 mars 2026

Spin Dynamics in Reduced Dimensions - Sarah Dunsiger (TRIUMF)

Historically, spin 1/2 Ising and Heisenberg systems on a two dimensional triangular lattice with nearest-neighbour antiferromagnetic exchange interactions are the archetypal examples of geometric magnetic frustration. The triangular lattice systems were the first to be proposed as candidates for a quantum spin liquid ground state, where there is an unusually high degree of entanglement of the spins and consequently the system is capable of supporting nonlocal excitations without ordering.

Whereas earlier investigations concentrated on insulating systems, there are an increasing number of studies of frustrated magnetism in metallic systems. Because the RKKY interaction is of a longer range than the superexchange interaction, the frustration effect in metallic compounds may be most evident in low carrier density systems. When quantum fluctuations become enhanced due to magnetic frustration, exotic phases such as complex spin density wave ordering or quantum spin liquids have been proposed. It is therefore clearly important to search for experimental realizations — rare-earth-based triangular lattice compounds are promising candidates.

Measurements of the spin lattice relaxation using muon spin relaxation (µSR) have been particularly valuable in the search for spin liquid behaviour. An introduction to spin resonance  techniques and their unique contributions to the study of magnetic excitations will be presented."