Magnetic structure of the conductive triangular-lattice antiferromagnet   PdCrO2
  We performed neutron single crystal and synchrotron X-ray powder diffraction experiments in order to investigate the magnetic and crystal structures of the conductive layered triangular-lattice antiferromagnet PdCrO2 with a putative spin chirality, which contributes to an unconventional anomalous Hall effect. We revealed that the ground-state magnetic structure is a commensurate and nearly-coplanar 120-degrees spin structure. The 120-degrees plane in different Cr layers seem to tilt with one another, leading to a small noncoplanarity. Such a small but finite non-coplanar stacking of the 120-degrees planes gives rise to a finite scalar spin chirality, which may be responsible for the unconventional nature of the Hall effect of PdCrO2. 
Hiroshi Takatsu, Gwilherm N\'enert, Hiroaki Kadowaki, Hideki   Yoshizawa, Mechthild Enderle, Shingo Yonezawa, Yoshiteru Maen...
cond-mat.str-el