title: Simultaneous Antiferromagnetic Order and Spin-Glass-like Behavior in MnAsO(4).
abstract: A low-temperature time-of-flight neutron powder diffraction study of a simple new solid, MnAsO(4), in a sample also containing 20% Mn(2)As(2)O(7) has been performed. MnAsO(4) orders magnetically at 14.5(5) K, and the unusual antiferromagnetic structure below this temperature has been determined. Only half of the Mn(3+) spins are ordered, and the remaining "idle" spins show some spin-glass behavior evidenced by susceptibility measurements. The ordered moment is reduced to a value of 2.6 &mgr;(B) by frustration. It is not possible to determine which of the two crystallographically inequivalent Mn sublattices is magnetically ordered and which is idle. The antiferromagnetic structure of the minority phase Mn(2)As(2)O(7) which orders at 10.5(5) K has also been determined.
authors.affiliation: Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga, Spain, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., and Departamento de Física Aplicada, Universidad de Málaga, 29071 Málaga, Spain.
authors.forename: Miguel A. G.
authors.initials: MA
authors.lastname: Aranda
authors.forename: J. Paul
authors.initials: JP
authors.lastname: Attfield
authors.forename: Elaine
authors.initials: E
authors.lastname: Batchelor
authors.forename: Greg P.
authors.initials: GP
authors.lastname: Shields
authors.forename: Sebastián
authors.initials: S
authors.lastname: Bruque
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gabás