Quantum oscillations and magnetic reconstruction in the delafossite PdCrO2

Abstract

We report quantum oscillation data on the metallic triangular antiferromagnet PdCrO2. We find that, to very high accuracy, the observed frequencies of PdCrO2 can be reproduced by reconstruction of the (nonmagnetic) PdCoO2 Fermi surface into a reduced zone. The reduced zone corresponds to a magnetic cell containing six chromium sites, giving a 3×3 in-plane reconstruction, and ×2 interplane reconstruction. The interplane ordering represents a reduction in lattice symmetry, possibly to monoclinic, and an associated lattice distortion is expected. In addition, we report a magnetic transition under an applied in-plane field that is probably equivalent to the spin-flop transition reported for CuCrO2, and present data on its field-angle dependence. We also report measurements of the resistivity of PdCrO2 up to 500 K.