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...

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...

Here we present a detailed study of the spinel CdEr2Se4 and show it to be a new instance of spin ice, the first one in an erbium material and the first one in a spinel. Definitive experimental evidence comes from the temperature dependence of the magnetic entropy, which shows an excellent agreement with the predicted behavior for a spin ice state. Crystal field calculations demonstrate that the...

Our former study reported that Fe-Sn spinel (Fe3-xSnxO4) was easily formed when SnO2 and Fe3O4 were roasted under CO-CO2 atmosphere at 900-1100 °C. However, the formation procedure is still unclear and there is a lack of theoretical research on the formation mechanism of the Fe-Sn spinel. In this work, the reaction mechanisms between SnO2 and Fe3O4 under CO-CO2 atmosphere were determined using ...

We demonstrate that the compressibility of spinel Si3N4 nanocrystals increases when the pressure is raised above ;40 GPa. Si3N4 nanocrystals initially exhibit an extremely high bulk modulus of 685~45! GPa. But, above 40 GPa, the bulk modulus is reduced to 415~10! GPa. Thus, a critical pressure of ;40 GPa was determined that signifies the onset of size-induced weakening of elastic stiffness in n...

Nanocrystals and nanoclusters of the room-temperature magnetic spinel CuCr(2)S(4) have been synthesized using a facile solution-based method. The synthesis involves hot injection of an excess of 1-dodecanethiol (1-DDT) into a boiling coordinating solvent containing CuCl(2) and CrCl(3)·6H(2)O. Using octadecylamine (ODA) as a solvent yields cube-shaped nanocrystals with an average size of 20 ± 2 ...

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...

The effects of Be additions on the oxidation behavior of ~-NiAl in moist air at 1000°C and borderline alumina-forming y (TiAI) + Laves Ti-Al-Cr based alloys at 800°C and 1000°C in dry and moist air were investigated. The addition of Be to ~-NiAl suppressed the formation of transient alumina, and resulted in the formation of a protective BeAl20 4 spinel phase. In dry air, the addition of Be to t...