Papers by Author: I.Z. Rahman

Abstract: Perovskites have gained attraction as electrode and interconnect materials for Solid Oxide Fuel Cells (SOFCs) due to their catalytic, ionic and electrical conductivities, chemical and thermal stabilities at higher temperatures. The operation and efficiency of SOFC depends mainly on the electrodes. Each electrode, anode and cathode, has demanding materials selection criteria. State of the art nickel-yittria stabilized zirconia cermet anodes are unable to work efficiently with hydrocarbon fuels and at intermediate operating temperature range (600-800°C). Hence, there is an increasing demand for the development of alternate anode materials to improve the fuel flexibility and efficiency of SOFCs. Perovskite based materials have oxygen ion vacancies depending on composition, temperature, and surrounding crystalline environment that impart mixed ionic and electronic conductivities to them. Since perovskite can accommodate all the elements in the periodic table they can offer excellent catalytic properties. The report is about the present status of perovskites based anode materials for SOFC application.

Abstract: In this paper, we report on structural and magnetic properties of NiZn ferrite powders prepared by chemical co-precipitation method and calcined at different temperatures. Structural, topological and compositional analyses were performed by XRD, SEM, AFM and EDX techniques. The cation distributions in Ni0.8Zn0.2Fe2O4 ferrites were investigated by XPS (Al K
radiation: h
=1486.6 eV). Particle sizes were measured using AFM techniques and results were compared with BET technique and magnetic measurements were carried out using a vibrating sample magnetometer at room temperature.

Abstract: This paper reports on the effect of Sm doping concentration on structural and static magnetic properties of electrodeposited NiFe thin films. A reduction of Ni concentration from 80 to 50 percent was observed as the Sm concentration increased from 0 to 25%. XRD analyses revealed that a transition from crystalline to partially disordered state occurred on the Sm-doped NiFe thin films and ultimately transformed to amorphous state at higher concentration. The saturation magnetization decreased to ~50% at 25% Sm doping as compared to that of NiFe thin films.