doi:10.1002/aelm.202400962engLafuerza, SaraBlasco, JavierEvangelisti, MarcoSubías, GloriaGracia, DavidPardo, José Á.Barriuso, EduardoTorrelles, XavierPadilla-Pantoja, JessicaCaicedo, José M.Santiso, JoséHigh‐quality epitaxial five‐layer aurivillius films with in‐plane ferroelectricity for electrocaloric coolingART-2025-144348High‐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.2025http://zaguan.unizar.es/record/16171610.1002/aelm.202400962http://zaguan.unizar.es/record/161716oai:zaguan.unizar.es:161716info:eu-repo/grantAgreement/ES/AEI/CEX2023-001263-Sinfo:eu-repo/grantAgreement/ES/DGA/E11-23Rinfo:eu-repo/grantAgreement/ES/DGA/E12-23Rinfo:eu-repo/grantAgreement/EC/H2020/101007825/EU/ULtra ThIn MAgneto Thermal sEnsor-Ing/ULTIMATE-IThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 101007825-ULTIMATE-Iinfo:eu-repo/grantAgreement/EC/H2020/101029019/EU/Exploring Aurivillius phases for Green Electrocaloric Refrigeration/EAGERThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 101029019-EAGERinfo:eu-repo/grantAgreement/ES/MICINN/CEX2021-001214-Sinfo:eu-repo/grantAgreement/ES/MICINN/CEX2023-001286-Sinfo:eu-repo/grantAgreement/ES/MICINN/PID2021-123276OB-I00info:eu-repo/grantAgreement/ES/MICINN/PID2021-124734OB-C21Advanced Electronic Materials (2025), 2400962 [10 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess