High-performance Fe(Se,Te) films on chemical CeO₂-based buffer layers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Superconductivity

Background:

• Fabricating iron-based coated conductors (CCs) requires epitaxial growth of Fe(Se,Te) on metallic substrates.
• The low structural anisotropy of Fe(Se,Te) allows for a simplified CC architecture compared to REBCO.
• A buffer layer is crucial for oriented growth and preventing diffusion from the metallic template.

Purpose of the Study:

• To investigate the growth of Fe(Se,Te) films on CeO2-based buffer layers using pulsed laser deposition.
• To evaluate the effect of a Fe(Se,Te) seed layer on the superconducting properties of the films.
• To demonstrate the feasibility of a simplified Fe-based CC architecture.

Main Methods:

• Pulsed laser deposition (PLD) for growing Fe(Se,Te) films.
• Chemical deposition of CeO2-based buffer layers.
• Transmission electron microscopy (TEM) for film characterization.
• Comprehensive measurement of current transport properties (J(θ, H, T)).

Main Results:

• Excellent Fe(Se,Te) film properties were achieved using a Fe(Se,Te) seed layer on CeO2-based buffer layers.
• Transmission electron microscopy revealed the seed layer's critical role in film quality.
• Superconducting transitions occurred around 16 K with critical current densities exceeding 1 MA/cm² at 4.2 K in self-field.
• In-field and angular behaviors were consistent with literature data.

Conclusions:

• The use of a Fe(Se,Te) seed layer significantly enhances the properties of Fe(Se,Te) films grown on CeO2-based buffer layers.
• These findings demonstrate the practical feasibility of fabricating simplified, cost-effective Fe-based coated conductors.
• The developed approach offers advantages in process simplification and cost reduction for superconducting wire production.