Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 12: Postersession DS

DS 12.14: Poster

Montag, 7. März 2016, 17:00–19:00, Poster A

Phonon, structural and magnetic properties of ordered double perovskite A₂BMnO₆ (A=La, Pr, Nd, Sm, Gd, Y, B=Co, Ni) thin films — •Christoph Meyer, Bernd Damaschke, Konrad Samwer, and Vasily Moshnyaga — I. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

B-site ordered double perovskites A₂BMnO₆ (A=rare earth; B=Co, Ni) with monoclinic P12₁/n1 structure are promising materials for spintronic applications due to ferromagnetic ordering, magnetodielectric coupling and multiferroic behavior. To study the influence of A- and B-site cations, we grew series of A₂BMnO₆ (A=La, Pr, Nd, Sm, Gd, Y; B=Co, Ni) thin films on SrTiO₃(111), SrTiO₃(100) and MgO (100) substrates by metalorganic aerosol deposition. The films were analyzed by X-ray diffraction (XRD), magnetization measurements (SQUID) and far-field Raman and tip-enhanced Raman spectroscopy (TERS). All films are epitaxially and obey monoclinic P12₁/n1 structure with superlattice reflections in the cubic [111] direction due to high degree of B-site ordering. Ferromagnetic ordering with high T_C and a strong A_g symmetry mode of B/MnO₆ octahedral stretching at ∼630−670 cm⁻¹ in the TERS and far-field Raman spectra were detected. Enhanced T_C and A_g mode frequency values for A₂NiMnO₆ compared to A₂CoMnO₆ and a systematic reduction of T_C and the stretching mode frequency by decreasing the A-site cation size were observed. Financial support by the DFG via project SFB 1073/B04 is gratefully acknowledged.