Magnetic ordering in ordered complex Cu perovskite probed by μμSR and neutron diffraction

Magnetic properties of antiferromagnetic (AF) B-site-ordered perovskite Ba22CuWO66 have been investigated by μμSR and neutron diffraction. Interesting features of this compound are the magnetic two-dimensionality and seemingly frustrating interactions between the nearest and the next-nearest s=12 spins of Cu2+2+. Zero-field μμSR experiments on a powder sample have shown the oscillating asymmetry below 28 K and the subsequent neutron diffraction experiment has confirmed the three-dimensional AF ordering presumably of the type-II on the face-centered lattice. The results suggest the dominance of the interaction between the next-nearest neighbor spins within the c-plane. Some contradictions, however, again arise to the expectations and explanations based on the seemingly equivalent nearest and next-nearest interaction paths. Nature of the magnetically ordered state is also interesting.