The processing and characterization of Pb(Mg1/3Nb2/3)O3 (PMN) powders for coating capacitor

Abstract

The present paper extensively demonstrates synthesis, characterization and electrical properties of relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN) sub-micron powders and PMN coatings on n-type Si substrates using sol–gel technique for capacitor applications. Transparent solutions were prepared from Pb, Mg and Nb based precursors, methanol and glacial acetic acid (GAA). The obtained solutions were dried at 80°C for 60min in air to form gel structure of PMN mixture and heat treated at 530°C for 3h and subsequently annealed at the temperature range of 800°C and 1000°C for 2h in air. After the sintering, the PMN powders were milled for 24h to obtain sub-micron powders. The powder size was measured using particle size machine. Finally, the powders were dispersed in alcohol and the obtained suspension was coated on n-type Si substrates. The films were dried at 50°C for 15min and subsequently were heat treated at 730°C for 30min in air to ensure its adhesion strength. Thermal, structural, microstructural, mechanical and electrical properties of the powder and the coatings were characterized by differential thermal analysis-thermo gravimeter (DTA/TG), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), refractometer, spectrophotometer and high resolution dielectric analyzer machines. The study provides a new insight on the sub-micron powders of PMN structure coated on Si semiconducting surface.