Direct measurement of electrocaloric effect in lead-free (Na0.5Bi0.5)TiO3-based multilayer ceramic capacitors

摘要

Multilayer ceramic capacitors (MLCCs) of lead-free NBT-based ceramics are produced and their electrocaloric effect (ECE) is characterised for the first time. Dense MLCCs with 97 mu m-thick active layers are successfully produced by tape casting. Dielectric permittivity measurements reveal the MLCCs to have properties similar with that reported for the corresponding bulk ceramics, including T-d similar to 50 degrees C and T-s similar to 100 degrees C. Direct ECE measurements also reveal agreement and confirm the previously reported tendency of the high-field ECE peak to shift towards T-s. The highest value of ECE, Delta T-max similar to 1.7K is measured at 90 degrees C under 90kV/cm. A low breakdown strength of 93kV/cm needs to be solved to realise stronger electric fields and achieve commercially viable ECE values.