Low temperature thermal conductivity measurement of magnetic delafossite PdCrO₂

Ultrapure delafossite metals are remarkably distinct from conventional metal oxides with their high electrical conductivity (some even exceeding that of noble metals) [1]. Thermal conductivity has previously been studied in PdCoO₂ [2] but never in the magnetic partner compound PdCrO₂. Here, we present such a study, down to sub-Kelvin temperatures. The high conductivities of delafossites necessitate samples with high aspect ratios to reach low temperatures with a reliable temperature gradient and minimal sample heating. I will discuss how this was achieved in our experiments.
[1] A. P. Mackenzie, Rep. Prog. Phys. 80, 032501 (2017).
[2] R. Daou, R. Frésard, S. Hébert, and A. Maignan, Phys. Rev. B 91, 041113 (2015).