Study On The Preparation And Dielectric Properties Of Mn Or Fe-doped Ba_xSr_1-xTiO₃ Ferroelectric Ceramics With Sol-Gel Process

Ba_xSr_1-xTiO3(BST) materials are being widely investigated as alternativedielectrics for ultra large integrated circuits DRAM storage capacitors, sensors, andmicrowave dielectrics due to its high dielectric constant, low leakage current, lowtemperature coeficient of electrical properties, small dielectric loss, linear relation ofelectric field and polarization, and low Curie temperature. However, whether or notBST can be successfully applied largely depends on more thorough understanding thematerial's properties.1. Ultra-fine BST powder was prepared by using Ba(CH₃COO)₂, Sr(CH₃COO)₂and Ti(OC₄H₉)₄ as starting materials via a Sol-Gel process. The pH value, the mainfactor have strong influence on the particle distribution of BST powder, wereinvestigated in detail. The investigation showed that the Sol-Gel process was aneffective method to produce ultra-fine BST powder.2. The influence of sin sintering temperature on the microstructure and dielectricproperties were investigated. Especially effects of Mn-doped and Fe-doped substitutein BST were investigated systematically. The results showed that: with the increasingof sintering temperature, the grain grows obviously and the ceramics become moredensity. Compared with doping just at Mn-doped and Fe-doped, the investigationshowed that the Mn-doped or Fe-doped could decrease the dielectric loss of BSTgreaterly.