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Abstract  

The enthalpy of formation for LiMyMn2–yO4 (M=Co, Cr, Li, Mg, Ni) was measured by a Tian-Calvet type high temperature isothermal microcalorimeter. The standard enthalpy of formation for LiMn2O4 at 876 K was evaluated to be H f 0=–1404.2±6.4 kJ mol–1. The partial substitution of Co and Ni for Mn decreased the absolute H f 0 value, while that of Cr and Mg for Mn increased the absolute H f 0 value. In the case of the partial substitution of Li for Mn, no marked change in H f 0 could be observed.

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discussion Figure 1 shows T and RT XRD patterns of the synthesized samples with the indicated zinc contents in the mixture. After RT annealing, reflections of only spinel phases were detected for all structures. After T annealing, the XRD

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Introduction Magnetic nanoparticles continue to evoke interest largely due to their prospective applicability. The spinel ferrite is a widely studied class of materials having remarkable magnetic and electric properties which

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ferrite components (Fe, Zn and Mn) in them was determined by ICP-AES. In both cases, the obtained material contains about 21 mol% less Zn than the assumed amount, but spinel phase occurs in a wide range of composition. The detected lower Zn content may be

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–3, 3–5 mm) and CAC as hydraulic binder (15 wt%). A spinel, MgO·Al 2 O 3 , was used as an additive in concrete mixture. A chemical composition of starting raw materials obtained by atomic absorption spectrophotometer, AAS Analyst 300, is given in Table

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Nano-crystalline Mn0.3Ni0.3Zn0.4Fe2O4 obtained by novel fumarato-hydrazinate precursor method

Synthesis, characterization and studies of magnetic and electrical properties

Journal of Thermal Analysis and Calorimetry
Authors: U. B. Gawas, V. M. S. Verenkar, and S. C. Mojumdar

Introduction Spinel ferrites are investigated in the recent years for their useful electrical and magnetic properties which find applications in information storage systems, magnetic bulk cores, magnetic fluids, microwave

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–titanium samples of Types A and B consisted of single-phase spinel. In the initial state their lattice parameters were a = 8.368 Å and a = 8.370 Å, respectively. This implies that vacuum annealing of the powder is followed by an increase in the lattice

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Abstract  

Sulphur substitution of oxygen in LiMn2O4 spinel destroyed the ideal symmetry of MnO6 octahedrons. In consequence, the phase change at about room temperature is strongly retarded, manifested by lowering heat of the transition and hysteresis of the temperature dependence of electrical conductivity. The optimal conditions for preparation of sulphur substituted spinel LiMn2O4–ySy have been determined.

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], magnetic high-density information storage [ 4 ], catalysis [ 5 ], energy storage [ 6 ], and gas sensors [ 7 ]. Ferrites can occur in several different crystal structure forms. Within this group, spinel is a kind of the most important structure that occurs

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