title: Coexisting ferromagnetic order and disorder in a uniform system of hydroxyhalide Co2(OH)3Cl.
abstract: Order or disorder often exists in a uniform spin system consisting of one kind of magnetic ion. Nevertheless, they rarely coexist in normal conditions. Our thermodynamic and microscopic magnetic studies of Co2(OH)3Cl, a distorted tetrahedral lattice compound with uniform Co2+ spin, demonstrate that the spins located on one corner of the tetrahedron are periodically ordered, but those on the other three are disordered below a ferromagnetic transition at TC=10.5 K. The partial order resembles that of the field-induced "kagomé-ice" state in spin ice pyrochlore compounds. Evidence suggests that a distortion in the tetrahedron is responsible for this partial ferromagnetic order in a zero field.
authors.affiliation: Department of Physics, Saga University, Saga 840-8502, Japan. zheng@cc.saga-u.ac.jp
authors.forename: X G
authors.initials: XG
authors.lastname: Zheng
authors.forename: T
authors.initials: T
authors.lastname: Kawae
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Nishiyama
authors.forename: C N
authors.initials: CN
authors.lastname: Xu