title: Formation of a three-dimensional network of V trimers in A2V13O22 (A=Ba, Sr).
abstract: We found that in A2V13O22 (A=Ba, Sr), which contains a trilayer slab of VO in the sodium-chloride structure with periodically missing ions, the trimerization of V ions occurs at 290 K (A=Ba) and 380 K (A=Sr). V trimers form a three-dimensional network, but some V ions remain untrimerized in these compounds. The suppression of magnetic susceptibility with trimerization and the existence of a Curie tail at low temperatures, together with the result of NMR measurement, indicate that the V trimers are spin singlet, whereas the untrimerized V ions have a magnetic moment; i.e., there is a spontaneous separation between nonmagnetic and magnetic ions in the crystal.
authors.affiliation: Department of Physics, Waseda University, Tokyo 169-8555, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Miyazaki
authors.forename: K
authors.initials: K
authors.lastname: Matsudaira
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: M
authors.initials: M
authors.lastname: Itoh
authors.forename: Y
authors.initials: Y
authors.lastname: Nagamine
authors.forename: S
authors.initials: S
authors.lastname: Mori
authors.forename: J E
authors.initials: JE
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.forename: M
authors.initials: M
authors.lastname: Takata
authors.forename: T
authors.initials: T
authors.lastname: Katsufuji