Speakers: Prof. B. Dabrowski (Dept. of Physics, Northern Illinois University, USA)
Place: Lecture hall of IoP, Slovanka
Presented in English
Organisers:
Department of Dielectrics
Abstract (abbreviated by J. Hlinka, full version enclosed):
Until only recently, it was proven challenging to achieve the displacive ferroelectric distortion in the d3 manganites because the [Mn4+-O] bonds have not been put under sufficient tension. By advancing elaborate synthesis processes, which are necessary to avoid the more stable hexagonal polymorphs, we were recently able to extended the substitution limit of the large size Ba ion in bulk Sr1-xBaxMnO3 samples to x = 0.45 with two-step “in situ” synthesis in a thermogravimetric furnace in flowing H2/Ar gas followed by oxygen anneal. The achieved perovskite ceramics exhibit ferroelectricity (TF > 300 K) and G-type antiferromagnetism (TN ~ 200 K) originating exclusively from the Mn cations.
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