The phenomenon of hydrogen induced changes in structural, optical and electrical properties of rare earth metals has been used to fabricate switchable mirrors. To improve the hydrogenation characteristics for switchable mirror applications, epitaxial, poly crystalline rare earth films, alloys of RE with Mg and RE-Mg multiplayer structures have been used. The electrical and optical switching has also investigated on macroscopic scale in nano-particulate layers having a large size distribution. The present proposal aims to investigate the hydrogen induced switching phenomenon on nano scale by using size selected gadolinium nano-particles. The role of the catalytic palladium during hydrogen loading and unloading will be investigated by synthesizing Gd-Pd pair nano-particles via gas phase synthesis and size fractionation. Stability of Gd nano-particle layers in oxygen ambient will be studied by measuring the changes in electrical and optical properties of the Gd layer as a function of exposure time in oxygen ambient. The dependence of hydrogenation characteristics on nano-particle size will be determined by studying electrical properties of nano-particle layers and individual nano-particles. This will be carried out using both macroscopic and nano-scaled characterization techniques like Hall effect and scanning tunnelling microscopy. Role of Pd will be ascertained by comparing the hydrogenation characteristics of Gd nano-particle layer having Pd over layer and Gd ¿Pd pair nano-particles. This study will open up new research direction towards, i) synthesis of complex material (Gd, Pd) in nanoparticle and pair-nanoparticle form, ii) study of hydrogen-rare earth nano-particle interaction and iii) fabrication of hydrogen induced nano-switches.
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