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Journal of Nanomaterials
Volume 2007, Article ID 52083, 7 pages
http://dx.doi.org/10.1155/2007/52083
Research Article

Effect of Current Density on Thermodynamic Properties of Nanocrystalline Palladium Capped Samarium Hydride Thin Film Switchable Mirrors

1Technische Physik, Universität des Saarlandes, Geb. 38, Postfach 151150, Saarbrücken 66041, Germany
2Thin Film Laboratory, Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India

Received 20 November 2006; Accepted 12 December 2006

Academic Editor: Rakesh K. Joshi

Copyright © 2007 Pushpendra Kumar and L. K. Malhotra. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A 55 nm samarium film capped with a 10 nm palladium overlayer switched from a metallic reflecting to a semiconducting, transparent in visible state during ex-situ hydrogen loading via electrochemical means in 1 M KOH electrolytic aqueous solution at room temperature. The switching between metal to semiconductor was accompanied by measurement of transmittance during hydrogen loading/unloading. The effect of current density on switching and thermodynamic properties was studied between dihydride state (FCC phase) and trihydride state (hexagonal phase). From the plateau of partial pressure of hydrogen at x=2.6, enthalpy of formation was calculated at different current densities. The diffusion coefficients and switching kinetics are shown to depend on applied current density.