Electrical properties of piezoelectric sodium-potassium niobate

Piezoelectric material is one of the most important components of the micro-electro mechanical system (MEMS). Most piezoelectrics have useful multi-functions for MEMS, e.g. sensor, actuator and transducer. An AFM cantilever, scanning mirror device and pumping system for a micro-chamber, are the typical applications of piezoelectric material on MEMS. Lead-based materials, e.g. lead zirconate titanate and lead lanthanum zirconate titanate, have been most popular among many piezoelectric materials. Recently alkali oxide materials, including potassium sodium niobate, have been given attention in view of their ultrasonic application and also as promising candidates for a piezoelectric non lead-based system. But this material system has been reported difficult to sinter only in the conventional method and it is possible to sinter by use of the hot isostatic press (HIP) method. In this report the synthesis process is, however, limited to the conventional solid state reaction method for the wide use of this material system. Several kinds of impurity doping into the base material is carried out in the sample preparation procedure. The physical, electrical properties and crystal structure of the several kinds of sodium-potassium niobate materials will be shown.