Condensed-Matter Physics & Materials Science Seminar

"Tailoring the twinning of DyBa2Cu3O7-x thin films with atomic-layer-by-layer molecular beam epitaxy"

Presented by Daniel Putzky, Max Planck Institute for Solid State Research, Germany

Monday, August 26, 2019, 1:30 pm — ISB Bldg. 734, Conf. Rm. 201 (upstairs)

In this talk I will present the work on high-quality, epitaxial DyBa2Cu3O7-x (DBCO) thin films grown by molecular beam epitaxy (MBE). In contrast to the previous DBCO growth by MBE using co-deposition technique, we have employed an atomic-layer-by-layer shuttering sequence with in-situ RHEED feedback. Films grown on LSAT (100), NGO (110) and STO (100) have a sharp superconducting transition above 80 K. Scanning-transition electron microscopy (STEM) shows atomically sharp substrate-film interface and the absence of stacking faults, unlike films previously grown by PLD. In the second part of the talk I will focus on the structural investigation using x-ray diffraction (XRD). In-plane scans at the KARA synchrotron confirm the epitaxial relationship to the substrate. In addition the formation of twin domains with the bulk-like orthorhombic crystal structure were observed. By reducing the film thickness the tetragonal to orthorhombic phase transition can be suppressed while the films still remain superconducting.

Hosted by: Tony Valla/Ilya Drozdov

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