Kovacova Veronika, Glinsek Sebastjan, Girod Stephanie, Defay Emmanuel
Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), 41 Rue du Brill, L-4422 Belvaux, Luxembourg.
Sensors (Basel). 2022 May 27;22(11):4049. doi: 10.3390/s22114049.
Lead scandium tantalate, Pb(Sc,Ta)O, is an excellent electrocaloric material showing large temperature variations, good efficiency, and a broad operating temperature window. In form of multilayer ceramic capacitors integrated into a cooling device, the device can generate a temperature difference larger than 13 K. Here, we investigate Pb(Sc,Ta)O in form of thin films prepared using the sol-gel chemical solution deposition method. We report the detailed fabrication process of high-quality films on various substrates such as c-sapphire and fused silica. The main originality of this research is the use of interdigitated top electrodes, enabling the application of very large electric fields in PST. We provide structural and electrical characterisation, as well as electrocaloric temperature variation, using the Maxwell relation approach. Films do not show a B-site ordering. The temperature variation from 7.2 to 15.7 K was measured on the Pb(Sc,Ta)O film on a c-sapphire substrate under the electric field of 1330 kV/cm between 14.5 °C and 50 °C. This temperature variation is the highest reported so far in Pb(Sc,Ta)O thin films. Moreover, stress seems to have an effect on the maximum permittivity temperature and thus electrocaloric temperature variation with temperature in Pb(Sc,Ta)O films. Tensile stress induced by fused silica shifts the "transition" of Pb(Sc,Ta)O to lower temperatures. This study shows the possibility for electrocaloric temperature variation tuning with stress conditions.
钽铌酸铅（Pb(Sc,Ta)O）是一种优异的电致热材料，具有较大的温度变化、良好的效率和较宽的工作温度窗口。以集成到冷却装置中的多层陶瓷电容器形式存在时，该装置可产生大于13 K的温差。在此，我们研究采用溶胶 - 凝胶化学溶液沉积法制备的钽铌酸铅薄膜。我们报告了在各种衬底（如c - 蓝宝石和熔融石英）上制备高质量薄膜的详细工艺。本研究的主要创新点在于使用叉指式顶部电极，能够在钽铌酸铅中施加非常大的电场。我们使用麦克斯韦关系方法提供结构和电学表征以及电致热温度变化。薄膜未显示B位有序。在14.5 °C至50 °C之间，在1330 kV/cm的电场下，对c - 蓝宝石衬底上的钽铌酸铅薄膜测量到温度变化为7.2至15.7 K。该温度变化是迄今为止钽铌酸铅薄膜中报道的最高值。此外，应力似乎对最大介电常数温度有影响，从而对钽铌酸铅薄膜中电致热温度随温度的变化产生影响。由熔融石英引起的拉伸应力使钽铌酸铅的“转变”向更低温度移动。这项研究表明了通过应力条件调节电致热温度变化的可能性。
