Micro-Structural Properties of YBa2Cu3O(7-x)/ZnO Nanorods on SrTiO3

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Investigating novel substrate architectures for high-temperature superconductors like Yttrium Barium Copper Oxide (YBCO) is crucial for advancing superconducting applications.
• Zinc Oxide (ZnO) nanostructures offer unique interfacial properties that could influence the performance of deposited thin films.

Purpose of the Study:

• To examine the local structural and interfacial properties of Yttrium Barium Copper Oxide (YBCO) films grown on Zinc Oxide (ZnO) nanorods/Strontium Titanate (STO) substrates.
• To understand the impact of ZnO nanorods on the structural characteristics and superconducting transition temperature (T(c)) of YBCO films.

Main Methods:

• Synthesis of vertically aligned ZnO nanorods on STO substrates via catalyst-free metal-organic chemical vapor deposition (MOCVD).
• Deposition of YBCO films on ZnO nanorods/STO templates using DC magnetron sputtering.
• Characterization using X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and Polarization-Dependent Extended X-ray Absorption Fine Structure (P-EXAFS) at the Cu K edge.

Main Results:

• YBCO films crystallized along their c-axes on ZnO nanorods/STO templates, with YBCO filling the inter-rod spaces.
• Clean interfaces were observed between YBCO/ZnO nanorods and ZnO nanorods/STO.
• Increased structural disorder in the CuO2 planes of YBCO on ZnO nanorods/STO was detected compared to YBCO on STO, leading to a reduced T(c) of approximately 50 K (vs. 93 K for YBCO/STO).

Conclusions:

• The presence of ZnO nanorods introduces structural disorder into the CuO2 planes of YBCO films.
• Grain boundaries within the YBCO films also contribute to the observed decrease in superconducting transition temperature.
• The findings highlight the sensitivity of YBCO superconductivity to interfacial structure and crystalline quality influenced by nanostructured substrates.