3.3.11 Sb-oxide spinels and Sb-oxide spinels with substitutions

2006 ◽  
pp. 469-475
Author(s):  
E. Agostinelli ◽  
D. Fiorani ◽  
A. M. Testa
Keyword(s):  
Oxide Spinels

Cation Distribution in Transition Metal Oxide Spinels: Thermodynamic and Kinetic Considerations

1983 ◽  
Vol 24 ◽  
Author(s):  
S. E. Dorris ◽  
D. S. Erickson ◽  
T. O. Mason
Keyword(s):  
Electrical Properties ◽  
Transition Metal ◽  
Metal Oxide ◽  
Cation Distribution ◽  
Transition Metal Oxide ◽  
Thermodynamics And Kinetics ◽  
Oxide Spinels ◽  
Kinetics Of ◽  
Thermoelectric Coefficient ◽  
Defect Reaction

ABSTRACTThe point defect reaction which governs the magnetic and electrical properties of transition metal oxide spinels is the distribution of cations between tetrahedral and octahedral sublattices. Two types of redistribution occur -- ionic and electronic. The thermodynamics and kinetics of these processes can be studied via the electrical properties, thermoelectric coefficient and conductivity.

ChemInform Abstract: STRUCTURAL CHARACTERIZATION OF CADMIUM-COPPER GALLIUM OXIDE SPINELS

1985 ◽  
Vol 16 (33) ◽  
Author(s):  
F. S. STONE ◽  
C. OTERO AREAN ◽  
J. S. DIEZ VINUELA ◽  
E. ESCALONA PLATERO
Keyword(s):  
Structural Characterization ◽  
Gallium Oxide ◽  
Oxide Spinels

scholarly journals Nanocrystalline Transition-Metal Gallium Oxide Spinels from Acetylacetonate Precursors via Solvothermal Synthesis

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 838 ◽  
Author(s):  
Daniel Cook ◽  
Reza Kashtiban ◽  
Klaus Krambrock ◽  
Geraldo de Lima ◽  
Humberto Stumpf ◽  
...  
Keyword(s):  
Transition Metal ◽  
Variable Temperature ◽  
Significant Proportion ◽  
Nanocrystalline Powders ◽  
Average Chemical Composition ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Transmission Electron ◽  
Oxide Spinels ◽  
X Ray Absorption

The synthesis of mixed-metal spinels based on substituted γ-Ga2O3 is reported using metal acetylacetonate precursors in solvothermal reactions with alcohols as solvents at 240 °C. New oxides of Cr, Mn and Fe have been produced, all of which are formed as nanocrystalline powders, as seen by high-resolution transmission electron microscopy (HR-TEM). The first chromium-gallium mixed oxide is thus formed, with composition 0.33Ga1.87Cr0.8O4 ( = vacant site). X-ray absorption near-edge spectroscopy (XANES) at the chromium K-edge shows the presence of solely octahedral Cr3+, which in turn implies a mixture of tetrahedral and octahedral Ga3+, and the material is stable on annealing to at least 850 °C. An analogous manganese material with average chemical composition close to MnGa2O4 is shown to contain octahedral Mn2+, along with some Mn3+, but a different inversion factor to materials reported by conventional solid-state synthesis in the literature, which are known to have a significant proportion of tetrahedral Mn2+. In the case of iron, higher amounts of the transition metal can be included to give an Fe:Ga ratio of 1:1. Elemental mapping using energy dispersive X-ray spectroscopy on the TEM, however, reveals inhomogeneity in the distribution of the two metals. This is consistent with variable temperature 57Fe Mössbauer spectroscopy that shows the presence of Fe2+ and Fe3+ in more than one phase in the sample. Variable temperature magnetisation and electron paramagnetic resonance (EPR) indicate the presence of superparamagnetism at room temperature in the iron-gallium oxides.

Magnetic behavior of the oxide spinels: Li0.5Fe2.5−2x Al x Cr x O4

Pramana ◽  
2002 ◽  
Vol 58 (5-6) ◽  
pp. 1031-1034 ◽  
Author(s):  
UN Trivedi ◽  
KB Modi ◽  
HH Joshi
Keyword(s):  
Magnetic Behavior ◽  
Oxide Spinels

Colossal magnetoresistance of oxide spinels, CoxMn3−xO4

1999 ◽  
Vol 39 (6) ◽  
pp. 311-317 ◽  
Author(s):  
John Philip ◽  
T.R.N Kutty
Keyword(s):  
Colossal Magnetoresistance ◽  
Oxide Spinels
Sign in / Sign up

Export Citation Format

Share Document