Fabrication of c-axis Oriented Zn_0.98Al_0.02O by a High-Magnetic-Field via Gelcasting and its Thermoelectric Properties

Abstract

The c-axis oriented Zn_0.98Al_0.02O was prepared by a combination of high magnetic field and gelcasting techniques, and its thermoelectric properties were examined. Optimized gelcasting conditions made it possible to align the particles preferentially along the c-axis within a short exposure time in the high magnetic field. The particle orientation was not degraded and disturbed by the gelation and subsequent processing. The degree of orientation was increased after sintering at 1400°C. The c-axis oriented specimen along the ab-plane showed an enhanced the electrical conductivity compared with the non-oriented specimen. The differences in the Seebeck coefficients between oriented and non-oriented specimens were a very small. This study indicated that applying the magnetic alignment via gelcasting method provides effective and versatile techniques to fabricate large and dense grain oriented materials without hindering the thermoelectric properties.