Magnetic order and multipoles in the 5d2 rhenium double perovskite Ba2YReO6

Ba2YReO6 is a double perovskite material where the Re5+ (d2) ions occupy a frustrated face-centered cubic lattice. Despite strong antiferromagnetic interactions between the Re ions, as indicated by a large negative Weiss constant θ=−616 K, spin freezing in Ba2YReO6 only occurs at 45 K. Since no long-range order of magnetic dipoles has previously been found in either muon spin rotation or neutron diffraction experiments below this temperature, …