Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Poster

DF 11.17: Poster

Mittwoch, 9. März 2016, 18:00–20:00, Poster E

Tilt engineering of spontaneous magnetisation and polarisation at room temperature in an oxide — •Michael Pitcher, Pranab Mandal, Matthew Dyer, Jonathan Alaria, Pavel Borisov, Hongjun Niu, John Claridge, and Matthew Rosseinsky — Department of Chemistry, University of Liverpool, Liverpool, UK

Combining spontaneous, switchable polarisation and magnetisation into a single phase multiferroic material is a major challenge in materials chemistry. Such materials with coupled electric and magnetic polarisation could provide the basis for low-energy high-density information storage devices, but are unlikely to be viable unless they can operate at (or close to) ambient temperatures. We have demonstrated a new strategy inspired by recent theoretical work on hybrid improper ferroelectrics, which describes how specific combinations of octahedral tilt distortions in layered (AO)(ABO₃)_n perovskites may be used to break inversion symmetry. We have applied these structural principles to a carefully selected (AO)(ABO₃)₂ parent phase with a strongly magnetic B-site sublattice, using chemical control to produce the desired polar distortion in a new series of compounds which order magnetically above room temperature. In this series, electrical polarisation and spontaneous magnetisation are induced simultaneously by control of the same structural distortion (an octahedral tilt). These properties are therefore coupled, as demonstrated by a linear magnetoelectric response, and are shown to coexist at temperatures of up to 330 K across a range of compositions.