Electrocaloric effects across room temperature in multilayer capacitors

Samples The active area of MLC1 of 85PST–15PMW was used for STEM. MLC1 of 85PST–15PMW and MLC1 of 90PST–10PMW were used for indirect EC measurements from which efficiency was evaluated and for direct measurements of EC temperature change that were converted to effective temperature change. MLC2 of 85PST–15PMW and MLC2 of 90PST–10PMW were crushed to form powders for XRD. MLC2 of 85PST–15PMW and MLC2 of 90PST–10PMW were used for zero-field calorimetry and direct measurements of EC heat. MLC3 of 85PST–15PMW and MLC3 of 90PST–10PMW were used for optical images. MLC4 of 85PST–15PMW and MLC4 of 90PST–10PMW were used for dielectric spectroscopy. MLC5 of 85PST–15PMW was tested for fatigue. MLC6 of 85PST–15PMW was used to measure leakage current. MLC fabrication Powders of high-purity Pb 3 O 4 , Ta 2 O 5 and MgWO 4 (Kojundo Chemical Laboratory Co., Ltd) and Sc 2 O 3 (Shin-Etsu Chemical Co., Ltd) were weighed, ball-milled for 16 h in distilled water with balls of partially stabilized zirconia, dried and then pulverized. The powder mixture was then calcinated at 850 °C for 4 h in air. Subsequent ball-milling that used partially stabilized zirconia balls with an organic solvent and binder resulted in a slurry for casting green sheets using the doctor blade technique. These green sheets were sliced, electroded by screen-printing Pt paste, stacked, pressed and cut to obtain green MLCs. …