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

Lafuerza, Sara ; Blasco, Javier ; Evangelisti, Marco ; Subías, Gloria ; Gracia, David ; Pardo, José Á. (Universidad de Zaragoza) ; Barriuso, Eduardo ; Torrelles, Xavier ; Padilla-Pantoja, Jessica ; Caicedo, José M. ; Santiso, José

Resumen: 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.

Idioma: Inglés

DOI: 10.1002/aelm.202400962

Año: 2025

Publicado en: Advanced Electronic Materials (2025), 2400962 [10 pp.]
ISSN: 2199-160X

Financiación: info:eu-repo/grantAgreement/ES/AEI/CEX2023-001263-S
Financiación: info:eu-repo/grantAgreement/ES/DGA/E11-23R
Financiación: info:eu-repo/grantAgreement/ES/DGA/E12-23R
Financiación: info:eu-repo/grantAgreement/EC/H2020/101007825/EU/ULtra ThIn MAgneto Thermal sEnsor-Ing/ULTIMATE-I
Financiación: info:eu-repo/grantAgreement/EC/H2020/101029019/EU/Exploring Aurivillius phases for Green Electrocaloric Refrigeration/EAGER
Financiación: info:eu-repo/grantAgreement/ES/MICINN/CEX2021-001214-S
Financiación: info:eu-repo/grantAgreement/ES/MICINN/CEX2023-001286-S
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2021-123276OB-I00
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2021-124734OB-C21

Tipo y forma: Article (Published version)

Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)