Magnetic ordering and spin waves in $\mathbf{N}{\mathbf{a}}_{0.82}\mathbf{Co}{\mathbf{O}}_2$

S. P. Bayrakci, I. Mirebeau, P. Bourges +6

Na${}_x$CoO${}_2$, the parent compound of the recently synthesized superconductor Na${}_x$CoO${}_2$:$y$H${}_2$O, exhibits bulk antiferromagnetic order below $\sim 20$ K for 0.75 $\le x\le$…