Nanostructured cation distribution in FeNbO4: A synchrotron powder diffraction and transmission electron microscopy investigation

• Published in: Journal of materials science Vol. 37; no. 20; pp. 4431 - 4436
• Main Authors: THEISSMANN, R, EHRENBERG, H, WEITZEL, H, FUE, H
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 15-10-2002; Springer Nature B.V
• Subjects: Antiphase boundaries; Cations; Condensed matter: structure, mechanical and thermal properties; Diffraction; Domains; Exact sciences and technology; High temperature; Inorganic compounds; Lead oxides; Materials science; Microscopy; Order disorder; Phase transitions; Physics; Salts; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Transmission electron microscopy; Wolframite; Iron Niobates; Inorganic compounds; Phase transformations; Transition element compounds; XRD; Nanostructures; Experimental study; Ion distribution; High-resolution methods; Transmission electron microscopy; Domain structure; Fabrication structure relation; Synchrotron radiation; Polymorphism; Crystal structure
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1020685426410

The real structure of FeNbO4 was determined by a combination of electron microscopy investigations and high resolution synchrotron powder diffraction. It is shown that the order-disorder phase transition from the orthorhombic high-temperature modification (α-PbO2-type structure) to the monoclinic low-temperature modification (wolframite-type structure) of FeNbO4 is translationengleich and leads to a domain structure that consists of a coherent mixture of the orthorhombic and the monoclinic modification. Domains of the monoclinic phase are separated by antiphase boundaries with an antiphase vector . The real structures of eight different samples have been investigated in terms of domain size and degree of cation ordering by peak-shape analysis and the ratio between integrated intensities of split-structure and fundamental reflections. The obtained real structure is correlated with the conditions of synthesis.