Phase purity and surface morphology of high-<i>J</i><sub>c</sub> superconducting Bi<sub>2</sub>Sr<sub>2</sub>Ca<sub>1</sub>Cu<sub>2</sub>O<sub>8+δ</sub> thin films

Author(s)
Sandra Keppert, Bernd Aichner, Rajdeep Adhikari, Bogdan Faina, Wolfgang Lang, Johannes D. Pedarnig
Abstract

Bi2Sr2Ca1Cu2O8+δ (Bi-2212) thin films with thicknesses less than 50 nm (<20 unit cells) are grown by pulsed laser deposition (PLD) onto (001) LaAlO3 (LAO) single crystal substrates. Phase-pure and smooth c-axis oriented Bi-2212 films with optimal oxygen doping, critical temperature Tc0 up to 86 K, and critical current density Jc(60 K) above 1 MA/cm2 are obtained for samples that are annealed in situ at temperatures below 700 °C. At higher temperature Bi-2212 films on LAO substrates partially decompose to non-superconducting impurity
phases, while films on MgO and SrTiO3 substrates are stable. The broadening ΔTc of the metal-to-superconductor resistive phase transition in magnetic fields is much larger for thin films of Bi-2212 as compared to YBa2Cu3O7. The magnetic field-induced suppression of Tc0 is stronger for Bi-2212 films containing impurity phases as compared to the phase-pure Bi-2212 films. The degradation of LAO substrate crystals after several steps of deposition and chemical removal of the Bi-2212 layer is investigated. New, commercially prepared substrates
provide Bi-2212 films with smallest surface roughness (3 nm) and strong out-of-plane texture. However, thin films of almost the same quality are obtained on re-used LAO substrates that are mechanically polished after the chemical etching.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Johannes Kepler Universität Linz
Journal
Applied Surface Science
Volume
636
No. of pages
10
ISSN
0169-4332
DOI
https://doi.org/10.1016/j.apsusc.2023.157822
Publication date
06-2023
Peer reviewed
Yes
Austrian Fields of Science 2012
103033 Superconductivity, 103018 Materials physics
Keywords
ASJC Scopus subject areas
Condensed Matter Physics, Surfaces, Coatings and Films, Surfaces and Interfaces
Portal url
https://ucrisportal.univie.ac.at/en/publications/phase-purity-and-surface-morphology-of-highjc-superconducting-bi2sr2ca1cu2o8-thin-films(01ede269-11c1-41da-9deb-9e1f7b2538fe).html