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%0 Thesis
%A Adiga, Shilpa
%T Crystal growth and scattering studies on two ferrites
%V 135
%I RWTH Aachen University
%V Dissertation
%C Jülich
%M RWTH-2017-00547
%@ 978-3-95806-183-5
%B Schriften des Forschungszentrums Jülich. Reihe Schlüsseltechnologien / Key  Technologies
%P iv, 150 Seiten : Illustrationen, Diagramme
%D 2016
%Z Druckausgabe: 2016. - Onlineausgabe: 2016.  - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2017
%Z Dissertation, RWTH Aachen University, 2015
%X In this thesis I will describe investigations of two ferrite systems:(1)	A detailed ferroelectric study of magnetite (Fe3O4)  Multiferroics, consisting of both ferroelectric and ferromagnetic phases, have attracted scientific and technological interest due possible magnetoelectric coupling between the phases. Such materials are very rare though, as conventional ferroelectricity requires an empty d-shell, preventing the presence of magnetism. Among unconventional mechanisms leading to ferroelectricity, multiferroicity due to charge ordering (CO) is a strong candidate for practical applications. However, proven examples are very rare as of yet. The 120 K Verwey transition (TV ) in magnetite, reported in 1939, is the classical example for charge ordering. Despite controversies regarding the existence of CO, magnetite has been proposed as one of the CO-based multiferroics. Although early experiments already indicated for example a magnetoelectric effect, those studies were mainly focused on complex low temperature structure rather than possible multiferroicity. In order to study the ferroelectric properties of magnetite by dielectric spectroscopy, a new dielectric measurement set-up was built at the institute. After an introduction and the description of experimental techniques, this thesis begins with the presentation of our newly built dielectric set-up and of the performed test experiments to standardize measurements of the dielectric constant.  The Verwey transition is very sensitive to oxygen stoichiometry. The oxygen stoichiometry was tuned by appropriate gas mixtures of  CO2 and CO or Ar(H2)4
%F PUB:(DE-HGF)3 ; PUB:(DE-HGF)11
%9 BookDissertation / PhD Thesis
%R 10.18154/RWTH-2017-00547
%U https://publications.rwth-aachen.de/record/681987