Science Daily February 1, 2023
An international team of researchers (USA – Ohio State University, Japan) has experimentally shown that an external electric field affects the velocity of the longitudinal acoustic phonons (vLA), thermal conductivity (κ), and diffusivity (D) in a bulk lead zirconium titanate–based ferroelectric. They found that phonon conduction dominates κ due to changes in the phonon dispersion, not in the phonon scattering. Since the ferron carries heat, that makes the amount of heat carried dependent on the electrical field. They wrote a new theory that relates an external electric field, the strain it induces in a ferroelectric, and ultimately how this strain affects the thermal conductivity. The theory is predictive, so it can be used it to find materials where the effect is much larger, ultimately leading to materials where it is large enough to be used in heat switches in everyday applications, like collection of solar power. The application of an electrical field to the material produced a 2% difference between maximum and minimum conductivity — as the new theory predicted would be the case… read more. Open Access TECHNICAL ARTICLE
Electric field dependence at 290 K of the ultrasound resonance around 340 kHz. Credit: SCIENCE ADVANCES, 1 Feb 2023, Vol 9, Issue 5Â Â Â Â Â