a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers with subnanometer rms roughness
Abstract
We demonstrate a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The trilayers are synthesized by ozone-assisted molecular-beam epitaxy. The thickness of the PrBa2Cu3O7−x layer is held constant at 8 nm, and the thickness of the YBa2Cu3O7−x layers is varied from 24 nm to 100 nm. X-ray diffraction measurements show all trilayers to have >97% a-axis content. The rms roughness of the thinnest trilayer is <0.7 nm, and this roughness increases with the thickness of the YBa2Cu3O7−x layers. The thickness of the YBa2Cu3O7−x layers also affects the transport properties: while all samples exhibit an onset of the superconducting transition at and above 85 K, the thinner samples show wider transition widths, ΔTc. High-resolution scanning transmission electron microscopy reveals coherent and chemically sharp interfaces and that growth begins with a cubic (Y,Ba)CuO3−x perovskite phase that transforms into a-axis oriented YBa2Cu3O7−x as the substrate temperature is ramped up.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 01, 2021
- Source ID
- 10.1063/5.0034648
Entities
People
- Berit H. Goodge
- Darrell G. Schlom
- Jiaxin Sun
- Jisung Park
- Jürgen Schubert
- Lena F Kourkoutis
- Y Eren Suyolcu
Organizations
- Air Force Office of Scientific Research
- Cornell University
- Leibniz Institute for Crystal Growth
- National Science Foundation