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DS: Fachverband Dünne Schichten

DS 31: Poster Session II

DS 31.1: Poster

Donnerstag, 15. März 2018, 11:15–13:15, Poster F

Morphology and crystallinity of Sr_xCo_yO_z films at different growth conditions and stoichiometry — •Patrick Schöffmann¹, Sabine Pütter¹, Jürgen Schubert², Willi Zander², Markus Waschk³, Paul Zakalek³, and Thomas Brückel³ — ¹Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching — ²Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich GmbH — ³Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH

Strontium cobaltite (SrCoO_{3− δ}) exists in two topotactic phases, depending on the oxygen content. SrCoO₃ is a ferromagnetic metal (T_C=305K) with perovskite structure while SrCoO_2.5 is an antiferromagnetic insulator(T_N=570K) with brownmillerite structure. Because of the multivalent Co states and high oxygen mobility it is a promising material for energy and information applications. [1]

We aim at growing thin films of SrCoO_{3− δ} by molecular beam epitaxy and filling the oxygen vacancies by oxygen plasma assisted annealing. Achieving a 1:1 stoichiometry by co-evaporation of Sr and Co requires tuning of the individual growth rates, which is not straightforward as there are three constituents with different sticking coefficients.

We present the effect of the growth conditions on the stoichiometry, crystallinity and morphology of Sr_xCo_yO_z films on STO and requirements for Sr₁Co₁O_2.5 films. First results of decreased oxygen vacancies by annealing in a low pressure oxygen atmosphere are discussed.

[1] H. Jeen et al., Nature Materials 12, 2013