Growth, Optimization and Characterization of co-substituted Cerium and Bismuth Garnet films for Integrated Magnetooptical.

Manda, Chandra Sekhar (2012). Growth, Optimization and Characterization of co-substituted Cerium and Bismuth Garnet films for Integrated Magnetooptical. Mémoire. Québec, Université du Québec, Institut national de la recherche scientifique, Maîtrise en sciences de l'énergie et des matériaux, 122 p.

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The symbols and special characters used in the original abstract could not be transcribed due to technical problems. Please use the PDF version to read the abstract The miniaturization of device dimensions is essential to the development of a new generation of ultra-comprehensive integrated optoelectronic circuits (ICs) that are based on magneto-optical (MO) materials. Epitaxial films of bismuth substituted iron garnets are among the most promising materials for the realization of such devices, thanks to their very high Faraday Rotation (FR). Gamet films have a wide operation frequency range in both the visible and infrared wavelengths making them ideal in many applications. The idea explored in the present work is to combine the improved magneto-optic properties induced by Cerium substitution in YIG with the structural stability granted by the ions of Bismuth when substituting for Yttrium, preventing the structural instability usually associated with high Ce doping levels. In view of future integration, the new remarkable material to be developed has to be also compatible with standard thin film technology. In this investigation, high-quality Ce2.2Bi0.8Fe5012 (CeBiIG) films, whose composition was selected to produce the highest MO response at communication wavelengths, were synthesized. High-quality Ce2.2Bi0.8Fe5012 films were grown by Pulsed Laser Deposition (PLD) on paramagnetic substrates of Gadolinium Gallium Garnet (GGG). Various growth parameters of the films were evaluated, inc1uding modification of the atmospheric conditions such as oxygen, argon, and a mixture of argon and hydrogen, in order to optimize the quality of the deposited films. The optimal deposition conditions were established. In particular, the best thin films were produced in an argon atmosphere. The CeBilG films deposited on (111) -oriented GGG substrates and treated in an argon atmosphere exhibits narrow mosaicity, suggest a good crystalline quality. In addition, morphological studies show a low roughness values within the range of 0.8-2 nm. Despite the volatile nature of the bismuth constituent in the grown films, the correct Bi composition has been confirmed by X-ray photoelectron spectroscopy (XPS). The Faraday rotation (FR) and the influence of film thickness on the performance of CeBilG magneto optical films have been studied. A value of the FR of 0.55 degrees/ µm at a wavelength of 1.5 µm has been reached, which is comparably higher than the FR values measured for other gamet films. The increased Faraday rotation coefficient in these films is most probably the result of the Bismuth ion doping into the dodecahedral sites of the CeBiIG gamet. In addition, these excellent MO film properties can be reproduced under the optimized conditions established.

Type de document:	Thèse Mémoire
Directeur de mémoire/thèse:	Pignolet, Alain
Co-directeurs de mémoire/thèse:	Morandotti, Roberto
Informations complémentaires:	Résumé avec symboles
Mots-clés libres:	CeBiIG; magnéto-optiques; yttrium; cérium; bismuth; grenat; gadolinium; gallium
Centre:	Centre Énergie Matériaux Télécommunications
Date de dépôt:	22 janv. 2013 16:39
Dernière modification:	24 nov. 2015 18:46
URI:	https://espace.inrs.ca/id/eprint/713

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