Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 77: Multiferroics
(Joint session of MA, DF, DS, KR and TT organized by MA)

TT 77.8: Vortrag

Donnerstag, 10. März 2016, 17:00–17:15, H34

Multiferroicity in off-stoichiometric Ga_xFe_1−xO₃ — •Konstantin Z. Rushchanskii, Stefan Blügel, and Marjana Ležaić — Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

The recently reported observation of room-temperature mutiferroic behavior in Ga_0.6Fe_1.4O₃ (GFO) [1] and є-Fe₂O₃ (eFO) [2] offers new perspectives for electronic devices whose operation is based on the switching of magnetic and electric ferroic ordering, as well as on the strong interaction between the magnetic and ferroelectric order parameters, such as multistate non-volatile memory cells. Unfortunately, the realistic microscopic switching mechanism in still not known for either of these materials. They are isostructural with polar Pna2₁ crystalline symmetry. In GFO, disorder in the occupancy of Ga and Fe sites is present, whereas eFO is a fully ordered compound. Their parallel study allows us to understand the influence of disorder on possible ferroelectric properties, and develop criteria to maximize the effect. We will present the results of an evolutionary-algorithm [3] based study of GaFeO₃-Fe₂O₃ solid solutions, (i.e., with increasing iron content). We will show the condition at which the proper ferroelectricity arises in GFO multiferroics and characterize the parameters of the ferroelectric phase transition. – We acknowledge financial support by Helmholtz Young Investigators Group Programme VH-NG-409 and through DFG-ANR (GALIMEO Consortium).

[1] A. Thomasson et al., J. Appl. Phys. 113, 214101 (2013); [2] M. Gich et al., Adv. Mater., 26, 4645 (2014); [3] http://uspex.stonybrook.edu