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DS: Fachverband Dünne Schichten

DS 21: Layer Properties I: Electronic Properties

DS 21.3: Vortrag

Mittwoch, 18. März 2020, 10:00–10:15, CHE 91

Magnetodielectric Effect and Interface Couplings in LaMnO3/LaNiO3 Superlattices — •Philipp Ksoll¹, Vladimir Roddatis², and Vasily Moshnyaga¹ — ¹1. Physikalisches Institut, Uni Göttingen — ²Institut für Materialphysik, Uni Göttingen

Multifunctional double perovskites, e.g. ferromagnetic insulating La2NiMnO6, have recently gained strong interest because of their rich physics and prospects for technological applications due to the magnetodielectric (MD) effect. To study the origin of MD coupling, epitaxial superlattices of (LaMnO3)n/(LaNiO3)n (LMO/LNO) with n varying from 20 u.c. down to one monolayer (n=1 yields La2NiMnO6) have been grown on Nb-doped SrTiO3(111) at relatively low (Tlow~650°C) and high (Thight~900°C) T by metalorganic aerosol deposition (MAD) technique, equipped with in situ optical ellipsometry. SLs grown at Tlow show an enhanced exchange bias field, HEB~40 Oe, and large coercive fields, Hc~800 Oe, as well as a suppressed saturation magnetization (msat,650°C~1/2*msat,900°C) as compared to those measured for SLs grown at 900°C. This means that the structure of interfaces and interfacial LMO/LNO magnetic coupling may be influenced by growth conditions. A relatively slow growth kinetics at 650°C seems to suppress the charge transfer between Mn and Ni cations, resulting an enhanced antiferromagnetic coupling between Mn3+ and Ni3+. Taking into account the data of in situ ellipsometry, we further performed measurements of dielectric constant for SLs with n=2, 5 at T=5-400 K and for frequencies, f=10E-6 - 2*10E6 Hz, to elucidate the role of LMO/LNO interfaces in the MD effect.