ULTIMATE-I
Published June 12, 2025 | Version v1
Publication Open

High-quality epitaxial five-layer aurivillius films with in-plane ferroelectricity for electrocaloric cooling

Authors/Creators

  • 1. ROR icon Universidad de Zaragoza
  • 2. Instituto de Nanociencia y Materiales de Aragón
  • 3. Instituto de Ciencia de los Materiales de Aragón (ICMA)
  • 4. Insituto de Nanociencia y Materiales de Aragón
  • 5. CSIC
  • 6. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST
  • 7. ROR icon Institut Català de Nanociència i Nanotecnologia

Description

High‐quality purely c‐axis oriented epitaxial thin films of the Aurivillius phase Sr2Bi4Ti5O18 with n = 5 (Sr,Bi)TiO3 perovskite‐like layers, are grown on SrTiO3 substrates by pulsed laser deposition. The highest crystalline quality is obtained with a 20 wt.% Bi‐excess target and average stacking order values in the proximity of the ideal value n = 5 are attained for an optimum deposition temperature of 650 °C. Scanning transmission electron microscopy reveals regions with n ranging from 4 to 6 around an average thickness of n = 5, in agreement with the X‐ray diffraction analysis. Interdigital electrodes are used to probe the in‐plane polarization and survey the electrocaloric properties. A maximum adiabatic temperature change of ΔT ∼ 0.95 °C for an electric field of 150 kV cm⁻¹ is observed at ≈135 °C. Larger values are expected at higher temperatures around the ferroelectric Curie temperature, TC. Since TC of Sr2Bi4Ti5O18 can be tuned by codoping, the findings pave the way toward a large electrocaloric effect at ambient temperature.

Files

High-Quality_Epitaxial_Five-Layer_Aurivillius_Film.pdf

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Additional details

Funding

European Commission
ULTIMATE-I - ULtra ThIn MAgneto Thermal sEnsor-Ing 101007825

Software

Repository URL
https://zaguan.unizar.es/record/161716?ln=es