SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 6: Poster
KFM 6.11: Poster
Dienstag, 28. März 2023, 17:00–19:00, P3
Dynamics of the electrocaloric effect in ferroelectric materials — •Jan Fischer, Daniel Hägele, and Jörg Rudolph — Ruhr-Universität Bochum, Germany
Ferroelectric materials are promising candidates for sustainable and environmentally friendly cooling applications due to their electrocaloric effect (ECE). The reversible temperature change Δ T results from a change of polarization P under adiabatic conditions. However, direct studies of the adiabatic temperature change are experimentally challenging. The vast majority of previous studies has used either indirect methods or slow temperature sensors. Systematic studies of dynamics of the ECE down to short timescales are completely missing.
Here, we present a direct and contactless method to study the dynamics Δ T(t) of the ECE with mK temperature resolution and µs temporal resolution via the infrared emission of the sample.1,2 The simultaneous recording of applied electric field E(t) and polarization P(t) transients gives further the opportunity to correlate the caloric with the dielectric properties thus opening new perspectives for a fundamental understanding. The technique also allows for measurements faster than the heat exchange between sample and environment achieving adiabatic conditions. Our method is applicable to a wide range of materials and requires no sophisticated sample processing.
We present measurements on different materials ranging from bulk ferroelectrics over complex relaxor ferroelectrics to thin polymer films.
1 J., Döntgen, et al., Applied Physics Letters 106, 3 (2015)
2 J., Döntgen, et al., Energy Technology 6, 8 (2018)