Details

Autor(en) / Beteiligte

• Magalhaes, B.
• Engelhardt, S.
• Molin, C.
• Gebhardt, S.E.
• Nielsch, K.
• Hühne, R.

Titel

Electrocaloric temperature changes in epitaxial Ba1−xSrxTiO3 films

Ist Teil von

• Journal of alloys and compounds, 2022-01, Vol.891, p.162041, Article 162041

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Epitaxial Ba1−xSrxTiO3 thin films with different thickness were grown by PLD on SrRuO3 buffered SrTiO3 substrates.•Sr doped samples show a broad maximum of permittivity indicating diffuse phase transitions and relaxor like behavior.•Electrocaloric temperature change increases with increasing film thickness and electric field. The basic aim of our study is to investigate the correlation between structural parameters and the electrocaloric effect in lead-free epitaxial Ba1−xSrxTiO3 (BSTO) based thin film architectures. Therefore, BSTO thin films with Sr contents of x = 0 to x = 0.3 were grown on SrRuO3 buffered SrTiO3 single crystalline substrates by pulsed laser deposition. Structural characterization verified an epitaxial growth for all Sr contents with an additional tetragonal distortion compared to bulk material. Temperature and frequency-dependent measurements of dielectric properties revealed increased permittivity values for thicker films with broad maxima indicating a diffuse phase transition. The temperature of maximum permittivity decreases with increasing Sr content, whereas polarization measurements indicate a relaxor-like behaviour in particular above room temperature. Adiabatic temperature changes were determined with the indirect method resulting in |ΔT| values of up to 2.9 K for a 680 nm thick BSTO layer with x = 0.3 at an applied electric field of 750 kV cm−1.