Aluminum substituted by cobalt of cobalt aluminates
having a nominal composition CoCoxAl2-xO4,
where x = 0, 0.5, 1, 1.5, and 2, were synthesized by
the thermal decomposition of complex precursors derived
from metal nitrate salts and glycine. All samples
were characterized using different techniques, XRD, FTIR,
TG, DTA, DSC, and TEM. XRD showed that all
samples have a spinel cubic crystal structure. Using
Debye–Scherrer formula, the calculated crystallite size
was found cobalt concentration dependent and varied
between 21 and 32 nm. Lattice parameter, X-ray density,
porosity, and unit cell volume were calculated to
show the effect of Al3+ substitution by cobalt on the
crystal structure of the investigated spinel samples.
Cation distribution and oxygen content into specific spinel
stoichiometry of all samples were calculated. The
optical, magnetic, and electrical properties were also
studied. The spinel nano cobalt aluminate (x = 0.5) having
Co/Al molar ratio of 1 showed the highest values of
saturation magnetization (Ms = 1.1 emu g−
1) and conductivity
(3.1 × 10–8 Ω−1 cm−1) compared to the other
ones. The color parameters (L*, a*, b*) were also measured.
All results were collected and discussed. |
