Dresden 2014 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 8: Multiferroics I (Joint Session with MA, DS, KR, TT)
DF 8.11: Vortrag
Dienstag, 1. April 2014, 12:15–12:30, BEY 118
Stoichiometric Effects on Crystal Quality in LuFe2O4 and YbFe2O4 — •Hailey Williamson1,2, Geetha Balakrisnan2, and Manuel Angst1 — 1Jülich Centre for Neutron Science JCNS-2 and Peter Grünberg Institut PGI-4, Forschungszentrum Jülich GmbH, Jülich, Germany. — 2Department of Physics, The University of Warwick, CV4 7AL, Coventry, UK
The multiferroic rhombohedral LnFe2O4 (Ln=Lu, Y, Yb, Tm, Ho and Er) system, which can be described as stacked hexagonal Fe bilayers separated by Lu monolayers, has been in focus since the discovery of interesting magnetic and electrical characteristics in LuFe2O4. The specific CO configuration within the Fe bilayers was initially thought to produce a ferroelectricity through cross polarization of the two layers of the bilayer. However our recent investigations indicate that the CO configuration is actually non-polar. Extensive research highlighted a large sensitivity to oxygen stoichiometry, where crystals grown in an excess/deficient oxygen partial pressure environment exhibit smeared glassy magnetic transitions and diffuse CO. Through fine tuning of the atmospheric conditions, crystals exhibiting 3D CO and magnetism were produced. Interest then spread to isostructural YbFe2O4, which has currently few detailed investigations. Single crystals of YbFe2O4 were grown in four different partial pressure atmospheres to view the effects of oxygen stoichiometry on the magnetism and CO. A series of macroscopic and microscopic measurements provided a detailed look into the effects of oxygen stoichiometry on the intrinsic characteristics as well as a comparison to that of its predecessor LuFe2O4.