Dresden 2017 – wissenschaftliches Programm
TT 72.7: Vortrag
Donnerstag, 23. März 2017, 16:30–16:45, HSZ 204
The response of a triangular antiferromagnet to anisotropic lattice distortion — •Dan Sun1, Jack Bartlett1,2, Jhuma Sannigrahi1, Pallavi Kushwaha1, Andrew Mackenzie1,2, and Clifford Hicks1,2 — 1Max-Planck Institute for Chemical Physics of Solids, Nöthnitzerstr. 40, Dresden, 01187, Germany — 2Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
The ground state of Heisenberg spins interacting antiferromagnetically on a triangular lattice is 120∘ antiferromagnetic order. We probe the effects of anisotropic lattice distortion on this phase using the material PdCrO2, which has highly-conducting Pd sheets that alternate with Mott-insulating CrO2 layers. The Cr spins order into a 120∘ phase at TN = 39 K. The conductivity of the Pd sheets can be measured to probe magnetic scattering across the transition. In the unstrained lattice, the resistivity has a sharp first-order-like step at TN. It persists with almost no change up to a compression of ∼ 0.2%, then broadens dramatically. This feature suggests a rigidity of the 120∘ phase at T ∼ TN against small perturbations, which we discuss in terms of magnetoelastic coupling and fluctuation effects.