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TT: Fachverband Tiefe Temperaturen

TT 18: Superconductivity: Poster

TT 18.34: Poster

Montag, 18. März 2024, 15:00–18:00, Poster C

YBCO heterostructures for SQUID-on-lever — Katja Wurster¹, •Simon Koch¹, Varun Harbola², Yu-Jung Wu², Reinhold Kleiner¹, Jochen Mannhart², and Dieter Koelle¹ — ¹Physikalisches Institut, Center for Quantum Science (CSQ) and LISA+, Universität Tübingen, Germany — ²Max Planck Institute for Solid State Research, Stuttgart, Germany

Scanning SQUID microscopy (SSM) is a powerful technique for imaging magnetic fields or dissipation processes. The use of the high-T_c cuprate superconductor YBa₂Cu₃O₇ (YBCO) combined with custom made Si AFM Cantilevers could enable SSM in the Tesla range and at temperatures up to about 80 K with a high spatial resolution. However, YBCO has a complex crystal structure and a small coherence length, which leads to a high sensitivity to defects on the atomic scale. High quality YBCO films can only be obtained by epitaxial growth on lattice-matched substrates. Therefore, the challenge with this approch is the integration of YBCO thin films on Si wafers. We intend to use Sr₃Al₂O₆ (SAO) or Sr₂CaAl₂O₆ (SCAO), which are lattice-matched to perovskite materials, such as SrTiO₃ (STO). SAO and SCAO can be dissolved in water, i.e. it can be used as a sacrificial layer for the realisation of free-standing single-crystalline perovskite thin films, including YBCO. We present our process for the fabrication of YBCO heterostructures based on pulsed laser deposition (PLD) and discuss the optimization of growth conditions and properties of the used materials. Finally, we present our preliminary attempts to transfer YBCO films onto Si surfaces.

Keywords: YBCO; thin film; freestanding membrane; Sr2CaAl2O6; SQUID