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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Postersession KFM

KFM 15.18: Poster

Donnerstag, 19. März 2020, 16:00–18:30, P2/1OG

Ferrimagnetic oxide substrates in the synthesis of multiferroic heterostructures — •Thomas Ruf and Reinhard Denecke — Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, D-04103, Leipzig

The aim of this work is to deposit ferroelectric BaTiO3 thin films on single crystalline ferrimagnetic oxide substrates Fe3O4 and Y3Fe5O12 (YIG) to couple both ferroic properties.

X-ray Photoelectron Spectroscopy (XPS) investigations with different YIG samples have been conducted. Single crystalline YIG on Gd3Ga5O12 and single crystal YIG exhibit enhanced stoichiometric ratio of Y/Fe, whereas polycrystalline nano powder YIG is close to the structural formula. Additionally, the epitactically grown sample reveals a reduced surface (enhanced content of Fe(II)). The observed stoichiometric deviations could be correlated to specific aspects of XPS, like high surface sensitivity of XPS (approx. 2 - 5 nm) and photoelectron diffraction.

Pulsed Laser Deposition of BaTiO3 on single crystalline Fe3O4 can be performed at room temperature in oxygen environment. In this way, the chemical integrity of the substrate is preserved, e.g. oxidation at higher temperatures to alpha-Fe2O3 is prevented. The crystallisation of the resulting amorphous material could be achieved by heating in ultra-high vacuum (UHV). Samples with different intended film thicknesses of deposited BaTiO3 precursor on Fe3O4 have been heated up to 650 ^∘C in UHV. Segregation of Ti⁴⁺-ions from the surface to the substrate has been monitored by XPS and X-ray Diffraction (XRD).