The spinel oxides Zn0.4Co0.6AlxFe2-xO4 (x=0.0, 0.25, 0.50, 0.75 & 1.0) have been synthesized in the solid state sintering process in air. X-ray diffraction measurements have been carried out in order to check the phase which showed single phase spinel structure for all the samples. Initial permeability, frequency dependence of the complex permeability sintered at different temperatures has been...

available online at http://meteoritics.org 1287 © Meteoritical Society, 2004. Printed in USA. The activity of chromite in multicomponent spinels: Implications for T-fO2 conditions of equilibrated H chondrites Ronit KESSEL,1* John R. BECKETT,1 Gary R. HUSS,2 and Edward M. STOLPER1 1Institute of Earth Sciences, The Hebrew University, Givat-Ra, Jerusalem, 91904, Israel 2Department of Geological Sc...

We report the synthesis of a wide range of single-crystal spinel platelets with exposed (111) faces, lateral dimensions in the micrometer range, and thicknesses of 20–50 nm, prepared by soft chemical dehydration of well crystallized layered precursors. This method enables the synthesis of the metastable composition NiCoAlO4, which cannot be prepared by conventional solid state synthesis. Becaus...

Glasses and single crystals have traditionally been used as optical windows. Recently, there has been a high demand for harder and tougher optical windows that are able to endure severe conditions. Transparent polycrystalline ceramics can fulfill this demand because of their superior mechanical properties. It is known that polycrystalline ceramics with a spinel structure in compositions of MgAl...

Introduction: Spinel minerals with 'normal' structure are common in extraterrestrial materials and can form via a large range of processes including nebular condensation, crystallization from liquid melts and sub-solidus metamor-phic reactions. Owing to their ability to accept a large range of cations in their crystal structures these minerals can be regarded as useful petrogenetic indicators w...

Electron energy-loss spectroscopy (EELS) attached to current transmission electron microscopes can probe not only element-selective chemical information, but also site-selective information that depends on the position that a specific element occupies in a crystal lattice. The latter information is exploited by utilizing the Bloch waves symmetry in the crystal, which changes with its orientatio...

Introduction: Melilite-free, spinel-, hibonitebearing spherules, a major type of refractory inclusion in CM2 chondrites, consist of phases that are predicted by thermodynamic calculations to condense from a cooling gas of solar composition but are not predicted to coexist with each other. Throughout updates and additions to the data base over the years, calculations [e.g. 1-3] consistently show...

A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe₂O₄) using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe₂O₄ particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and nitrogen...

A spinel ferrite of the system NiSixFe2-xO4 with (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were studied via IR, Xray spectra and cation distribution. The X-ray pattern confirmed the spinel cubic structure of all Si contents. The lattice parameters estimated as a function of Si contents indicated a slight decrease of lattice parameter up to 0.2. The grain size increases with increasing Si content up t...

Modified Li-rich layered cathode Li(Li0.2Mn0.54Ni0.13Co0.13)O2 has been synthesized by a simple strategy of using surface treatment with various amounts (0-30 wt.%) of Super P (carbon black). Based on detailed characterizations from X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy...