The polycrystalline manganite La0.75Sr0.25MnO3 prepared by an alternative carbonate precipitation route reveals the rhombohedral perovskite structure. Magnetization isotherms measured up to 2 T are used to determine Curie temperature of 332 K by means of Arrott plot. Maximum of magnetic entropy change is found at Curie temperature. The relative cooling power equal to 64 J/kg for 1.5 T magnetic ...

Zinc oxide (ZnO) is a promising material which gained increasing interest in recent years owing to its preparation methods and remarkable performances. The paper presents the most common techniques for the synthesis of ZnO nanoparticles, such as mechanochemical process, precipitation, sol-gel method, solvothermal and hydrothermal processes. Due to their optical, mechanical, chemical and electri...

................................................................................... viii CHAPTER 1. INTRODUCYION ........................................................... 1 1.1 Motivation ................................................................................. 1 1.2 Outline ..................................................................................... 2 CHAPTER 2. SOL-GEL PHOT...

............................................................................................................... XVII CHAPTER 1: INTRODUCTION ................................................................................... 1 1.1 NANOTECHNOLOGY ................................................................................................ 1 1.2 SUPERPARAMAGNETIC IRON OXIDE NANOPARTICLES ........

High quality manganese oxide thin films with smooth surfaces and even thicknesses have been prepared with a nonaqueous sol-gel process involving reduction of tetraethylammonium permanganate in methanol. Spin-coated films have been cast onto soft glass, quartz, and Ni foil substrates, with two coats being applied for optimum crystallization. The addition of alkali metal cations as dopants result...

to improve the corrosion protection of copper metal, 0.01m concentration of 1h-1,2,4-triazole-3-thiol (tat) was incorporated into the hybrid sol-gel monolayers containing 3-glycidoxypropyltrimethoxysilane (gptms) and tetraethoxysilane (teos). it was further subjected to hydrolysis and condensation reaction to form a sol-gel matrix. the tat-doped hybrid sol-gel coating was applied over the coppe...

Ethyl acetoacetate modi®ed aluminium sec-butoxide can be hydrolysed and gelled with alkaline, neutral or acidic media within a pH range of 3.0±8.5. Alumina precipitation occurs if pH values at any point in the sol±gel transition are outside this range. Nine di€erent gelling agents have been evaluated for pH dependence of gel point. Based on stoichiometric considerations, only those systems with...

Light transducing phycobiliproteins are encapsulated in optically transparent sol-gel matrices. Absorption and fluorescence spectroscopies are used to characterize the effect of the sol-gel encapsulation on the conformation and aggregation states of the three major phycobiliproteins present in phycobilisomes: phycoerythrin, phycocyanin, and allophycocyanin. It is found that the effects of sol-g...

In this paper, indium tin oxide (ITO) nanoparticles has been prepared by chemical methods under given conditions with solution of indium chloride (InCl3·4H2O), tin chloride (SnCl4·5H2O) in ammonia solution. The samples were characterized by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) analyses after heat treatments. The SEM results showed that, the size of the ITO particles pr...

Ridge and buried channel waveguides were fabricated on different substrates such as SiO2-on-Si, Si, glass wafers and Printed Circuit Boards by a sol-gel processing together with a photolithography process using photopatternable hybrid sol-gel materials. Thick sol-gel films of up to 100 microns were developed using a modified sol-gel process and ridge waveguides with vertical smooth sidewalls we...