Anion Vacancy Distribution and Magnetism in the New Reduced Layered Co(II)/Co(I) Phase LaSrCoO3.5 - x

• Published in: Chemistry of materials 2000-08, Vol.12 (8), p.2182-2195
• Main Authors: Hayward, M. A, Rosseinsky, M. J
• Format: Article
• Language: English
• Subjects: Antiferromagnetics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic compounds; Magnetic properties and materials; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Studies of specific magnetic materials; Water, oxides, hydroxides, peroxides
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm9906811

The new reduced K2NiF4 Co(II) phase, LaSrCoO3.5 - x , is prepared by reduction of the Co(III) containing LaSrCoO4 using H2 gas and the new hydride solid−solid reduction methods. The hydride route is superior in both crystallinity and control of phase purity and allows access to reduced phases containing substantial concentrations of Co(I). The anion vacancies are located within the MO2 planes of the K2NiF4 structure but do not prevent the onset of long-range antiferromagnetic order:  the magnetic structure is refined using a noncollinear model consistent with the tetragonal crystal symmetry.