Sushant Kumar

Les mat riaux qui pr sentent plus d'une propri t ferro que primaire, savoir le ferromagn tisme, la ferro lectricit et la ferro lasticit , sont connus sous le nom de mat riaux multiferro ques. Ces mat riaux offrent des possibilit s d'applications potentielles dans les dispositifs de stockage, les capteurs, les dispositifs spintroniques et les r actions photocatalytiques. BiFeO3 est le seul mat riau multiferro que qui pr sente une temp rature de Neel antiferromagn tique de type G de 653K et une temp rature de Curie ferro lectrique de 1100K, toutes deux sup rieures la temp rature ambiante. BiFeO3 poss de des propri t s multiferro ques temp rature ambiante, mais il pr sente galement des fuites de courant importantes dues des d fauts, des lacunes d'oxyg ne et de faibles propri t s ferro lectriques, ce qui limite ses propri t s. Pour r duire ces limitations, le dopage du mat riau de transition peut tre effectu la place du fer. Ce livre pr sente la synth se ainsi que les tudes structurelles, optiques et photocatalytiques des nanoparticules de ferrite de bismuth (BiFeO3) et de ferrite de bismuth dop au nickel (BiFe1-xNixO3).

I materiali che presentano pi di una propriet ferromagnetica primaria, ossia ferromagnetismo, ferroelettricit e ferroelasticit , sono noti come materiali multiferroici. Questi materiali offrono la possibilit di potenziali applicazioni in dispositivi di stoccaggio, sensori, dispositivi spintronici e reazioni fotocatalitiche. Il BiFeO3 l'unico materiale multiferroico che ha una temperatura di Neel antiferromagnetica di tipo G 653K e una temperatura di Curie ferroelettrica 1100K, entrambe superiori alla temperatura ambiente. Il BiFeO3 contiene propriet multiferroiche a temperatura ambiente, ma mostra anche una grande dispersione di corrente dovuta a difetti, vacancy di ossigeno e basse propriet ferroelettriche che ne limitano le propriet . Per ridurre queste limitazioni, possibile drogare il materiale di transizione al posto del ferro. Questo libro rappresenta la sintesi e gli studi strutturali, ottici e fotocatalitici della ferrite di bismuto (BiFeO3) e delle nanoparticelle di ferrite di bismuto drogate con nichel (BiFe1-xNixO3).

Os materiais que apresentam mais do que uma propriedade f rrica prim ria, ou seja, ferromagnetismo, ferroeletricidade e ferroelasticidade, s o conhecidos como materiais multiferr icos. Estes materiais oferecem possibilidades de aplica es potenciais em dispositivos de armazenamento, sensores, dispositivos spintr nicos e reac es fotocatal ticas. O BiFeO3 o nico material multiferr ico que tem uma temperatura de Neel antiferromagn tica do tipo G 653K e uma temperatura de Curie ferroel ctrica 1100K, ambas acima da temperatura ambiente. O BiFeO3 cont m propriedades multiferr icas temperatura ambiente, mas tamb m apresenta grandes fugas de corrente devido a defeitos, vac ncia de oxig nio e baixas propriedades ferroel ctricas, o que limita as suas propriedades. Para diminuir estas limita es, pode ser efectuada a dopagem de material de transi o em vez de ferro. Este livro apresenta a s ntese, bem como os estudos estruturais, pticos e fotocatal ticos de nanopart culas de ferrite de bismuto (BiFeO3) e de ferrite de bismuto dopada com n quel (BiFe1-xNixO3).

Die Materialien, die mehr als eine prim re ferroische Eigenschaft aufweisen, d. h. Ferromagnetismus, Ferroelektrizit t und Ferroelastizit t, werden als multiferroische Materialien bezeichnet. Diese Materialien bieten M glichkeiten f r potenzielle Anwendungen in Speicherger ten, Sensoren, spintronischen Ger ten und photokatalytischen Reaktionen. BiFeO3 ist das einzige multiferroische Material, das eine antiferromagnetische Neel-Temperatur vom G-Typ ( 653 K) und eine ferroelektrische Curie-Temperatur ( 1100 K) hat, die beide ber der Raumtemperatur liegen. BiFeO3 weist bei Raumtemperatur multiferroische Eigenschaften auf, zeigt aber aufgrund von Defekten und Sauerstoffleerstellen einen hohen Leckstrom und geringe ferroelektrische Eigenschaften, was seine Eigenschaften einschr nkt. Um diese Einschr nkungen zu verringern, kann anstelle von Eisen eine Dotierung mit einem bergangsmaterial vorgenommen werden. In diesem Buch werden die Synthese sowie die strukturellen, optischen und photokatalytischen Studien von Bismut-Ferrit (BiFeO3) und Nickel-dotierten Bismut-Ferrit (BiFe1-xNixO3) Nanopartikeln dargestellt.

This brief covers novel techniques for clean hydrogen production which primarily involve sodium hydroxide as an essential ingredient to the existing major hydrogen production technologies. Interestingly, sodium hydroxide plays different roles and can act as a catalyst, reactant, promoter or even a precursor. The inclusion of sodium hydroxide makes these processes both kinetically and thermodynamically favorable. In addition possibilities to produce cleaner hydrogen, in terms of carbon emissions, are described. Through modifications of steam methane reformation methods and coal-gasification processes, from fossil as well as non-fossil energy sources, the carbon dioxide emissions of these established ways to produce hydrogen can significantly be reduced. This brief is aimed at those who are interested in expanding their knowledge on novel techniques and materials to produce clean hydrogen and capture carbon dioxide at a large-scale. The detailed thermodynamic analysis, experimental findings and critical analysis of such techniques are well discussed in this brief. Therefore, this book will be of great interest and use to students, engineers and researchers involved in developing the hydrogen economy as well as mitigating carbon dioxide emissions at a large-scale.