Regensburg 2022 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 20: Poster

DS 20.37: Poster

Mittwoch, 7. September 2022, 16:00–18:00, P3

Stabilization of ferromagnetic metallic ground state in epitaxial (La_1−yPr_y)_0.7Ca_0.3MnO₃ /SrTiO₃ thin films by using buffer layers — •Pia Henning¹, Karen Stroh¹, Vitaly Bruchmann-Bamberg¹, Oleg Shapoval², and Vasily Moshnyaga¹ — ¹Erstes Physikalisches Institut, Georg-August-Universitat-Göttingen, Gottingen, Germany — ²IIEN, Academy of Sciences of Republic Moldova, Chisinau, Republic of Moldova

(La_1−yPr_y)_0.7Ca_0.3MnO₃ (LPCMO) is an A-site substituted perovskite manganite, mostly known for the colossal magnetoresistance (CMR) effect. Relatively thick, d=50-100 nm, and stress-free LPCMO films with coupled ferro/paramagnetic and metal/insulator transition (MIT) and CMR ∼10⁴% can be heteroepitaxially grown by the metalorganic aerosol deposition technique on MgO(200) substrates, where strain relief occurs due to misfit dislocations. However, thin LPCMO films d<20 nm on MgO(200) do not show MIT and CMR. Alternatively, LPCMO/SrTiO3 (LPCMO/STO) films grow coherently strained and with smooth surface morphology, however lacking the MIT and CMR even for d>50 nm. To obtain epitaxial LPCMO films with optimal metal-insulator transition sharpness and temperature we have employed a strain-engineered LaAlO₃ buffer layer to bridge the lattice mismatch of the LPCMO film and SrTiO₃(100) substrate. The influence of LaAlO₃ buffers on the magnetic and electric properties of epitaxial LPCMO films was studied. A high-quality growth of LPCMO/LAO/STO films and stabilization of the ferromagnetic-metallic phase for 10 nm thick LPCMO films were demonstrated.