We report the particle size dependent magnetic behaviour in the antiferro-magnetic spinel CoRh 2 O 4. The nanoparticles were obtained by mechanical milling of bulk material, prepared under sintering method. The XRD spectra show that the samples are retaining the spinel structure. The particle size decreases from 70 nm to 16 nm as the milling time increases from 12 hours upto 60 hours. The magne...

A thorough consideration of the relation between the lattice parameters of 185 binary and ternary spinel compounds, on one side, and ionic radii and electronegativities of the constituting ions, on the other side, allowed for establishing a simple empirical model and finding its linear equation, which links together the above-mentioned quantities. The derived equation gives good agreement betwe...

Cr-spinel [(Mg, Fe2+)(Cr, Al, Fe3+)2O4)] is a common mineral in the ultramafic core of Duke Island complex southeastern Alaska, US. grains with an unmixed texture have been observed dunite and wehrlite complex. Inhomogeneous ratio Cr/(Al + Cr Fe3+) <0.37 prominent dunite. The inhomogeneous consists two completely different compositions: Al-rich Cr-spinel, Fe3+-rich wide range content (from 1...

High voltage spinel LiNi(0.5)Mn(1.5)O(4) is a very promising cathode material for lithium ion batteries that can be used to power hybrid electrical vehicles (HEVs). Through careful control of the cooling rate after high temperature calcination, LiNi(0.5)Mn(1.5)O(4) spinels with different disordered phase and/or Mn(3+) contents have been synthesized. It is revealed that during the slow cooling p...

Samples of nickel cobaltite, a mixed oxide occurring in the spinel structure which is currently extensively investigated because of its prospective application as ferromagnetic, electrocatalytic, and cost-effective energy storage material were prepared in the form of nanocrystals stabilized in a highly porous silica aerogel and as unsupported nanoparticles. Nickel cobaltite nanocrystals with av...

The feasibility of stabilizing nickel-laden sludge from commonly available Al-rich ceramic precursors was investigated and accomplished with high nickel incorporation efficiency. To simulate the process, nickel oxide was mixed alternatively with gamma-alumina, corundum, kaolinite, and mullite and was sintered from 800 to 1480 degrees C. The nickel aluminate spinel (NiAl2O4) was confirmed as the...

Development of efficient, affordable electrocatalysts for the oxygen evolution reaction and the oxygen reduction reaction is critical for rechargeable metal-air batteries. Here we present lithium cobalt oxide, synthesized at 400 °C (designated as LT-LiCoO2) that adopts a lithiated spinel structure, as an inexpensive, efficient electrocatalyst for the oxygen evolution reaction. The catalytic act...

Ordered mesoporous Fe(3)O(4) with crystalline walls (inverse spinel structure) has been synthesized for the first time, representing to the best of our knowledge, the first synthesis of a reduced mesoporous iron oxide. Synthesis was achieved by reducing ordered mesoporous alpha-Fe(2)O(3) (corundum structure) to Fe(3)O(4) spinel then to gamma-Fe(2)O(3) by oxidation, while preserving the ordered ...

The enhanced interest of the researchers in nanoobjects is due to the discovery of unusual physical and chemical properties of these objects, which is related to manifestation of so-called ‘quantum size effects‘. These arise in the case where the size of the system is commensurable with the de-Brogli wavelengths of the electrons, phonons or excitons propagating in them.A key reason for the chan...

PVP functionalized metal oxide coatings on spinel nanoparticles demonstrated significantly improved rate characteristics under extensive cycling at 65 degrees C and exhibited over 100% improved capacity retention compared to the bare counterpart.