Crystal chemistry, structure and magnetic properties of the Cu(Mo x W1− x )O4 solid solution series

• Published in: Philosophical magazine (Abingdon, England) Vol. 88; no. 8; pp. 1235 - 1258
• Main Authors: Schwarz, B., Ehrenberg, H., Weitzel, H., Senyshyn, A., Thybusch, B., Knapp, M., McIntyre, G.J., Fuess, H.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.03.2008; Taylor and Francis; Taylor & Francis
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; diffraction; Exact sciences and technology; Exchange and superexchange interactions; Inorganic compounds; magnetic oxides; Magnetic properties and materials; magnetic structure; Magnetically ordered materials: other intrinsic properties; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; transmission electron microscopy; Profile refinement; Stoichiometry; Crystal form; Magnetization; Coupling constants; Statistical distribution; Neutron diffraction; Crystal chemistry; Copper Molybdates Tungstates; Ion distribution; Unit cell; Monocrystals; Transmission electron microscopy; Solid solutions; Experimental design; Superexchange interactions; Magnetic structure; Electron probes; Synchrotron radiation; Magnetic properties; Crystal structure; Physical Sciences
• DOI: 10.1080/14786430802106237
• ISSN: 1478-6435

For a solid solution series the common description of a crystal as a homogeneous solid formed by a repeating, three-dimensional pattern of a unit cell is in principle no longer applicable, taking the statistical chemical distribution of the substituting ions into account. The Cu(Mo x W 1−x )O 4 solid solution series represents an appropriate system to investigate how this chemical distribution affects the details of the crystal structure: Due to different coordination preferences of the isovalent diamagnetic ions W and Mo, a decisive magnetic exchange path couples ferromagnetically in CuWO 4 , but antiferromagnetically in the isostructural compound CuMoO 4 -III. From the investigations of the magnetic properties of the solid solution series it can be inferred for a certain range of stoichiometries that the Mo/W cation disorder of the solid solution series does not result in a corresponding disordered distribution of magnetic coupling constants but in the formation of a super structure of them. The magnetic superexchange here acts as a very sensitive probe for local bonding geometries. Consequently, in the solid solution cooperative structural processes dominate over individual coordination preferences. In the present work Cu(Mo x W 1−x )O 4 powder samples are characterized with high-resolution synchrotron diffraction, magnetization measurements and neutron diffraction. Cu(Mo x W 1−x )O 4 single crystals are characterized by electron probe micro-analysis, transmission electron microscopy, X-ray structure refinement and profile analyses, magnetization measurements and diffraction with 'white' and monochromatic neutrons.