[EDP2] Digital, Quantum Information Technology, Materials and Fabrication

[EDP2-12] Anisotropy and Strain Characterization in RCE Grown YBCO Thin Films for Superconducting Applications

*Nicole Y Chin¹, Rochelle Y Qu¹, Francisco Guzman², Sreekar Vattipalli¹, Jay C LeFebvre¹, Xiaoqing Pan², Shane A Cybart¹ (1. University of California, Riverside (United States of America), 2. University of California, Irvine (United States of America))

Keywords:

YBCO,Anisotropy,GIXRD,XRD,TEM

Superconductors present significant opportunities for enhancing energy efficiency, with the potential to transform applications such as high-performance computing while reducing environmental impact. YBa₂Cu₃O_7-δ (YBCO) is a cuprate superconductor with excellent electrical properties, making it a key material for superconducting devices and for fabricating Josephson junctions. Reactive co-evaporation (RCE) grown films enable uniform film deposition over large areas and have been used extensively for high-quality, scalable YBCO growth. A comprehensive study on RCE grown YBCO thin films can provide a better understanding of the effects using different substrates of sapphire, lanthanum aluminate (LAO), and magnesium oxide (MgO), as well as varying film thickness. X-ray diffraction (XRD) analysis using the Grazing Incidence X-ray Diffraction (GIXRD) technique measured the in-plane a and b directions to investigate anisotropy for improving superconducting electronics. θ-2θ scans, rocking curves, and pole figures were also measured to compare the lattice parameters, crystalline quality, and texture orientation. An analysis of a 45 nm YBCO film on sapphire using transmission electron microscopy (TEM) provides visual insight into varying strain throughout the lattice. These films revealed anisotropy between the a and b directions with differences in lattice parameters. These results correlate with prior anisotropy electrical measurements and photoemission electron microscopy (PEEM) surface measurements. The thicknesses, type of substrate, and being buffered or unbuffered showed significant differences in the material properties of the films. Thicker sapphire films exhibited less strain and different preferred orientations. Films grown on unbuffered MgO substrates exhibited less strain in the a direction. I will highlight and discuss how these observed changes in film characteristics can be used to optimize the YBCO thin film growth for device applications.