Effect of Mn doping on the microstructure and dielectric properties of BaHf0.1Ti0.9O3 ceramics

Pure and Mn-doped barium hafnate titanate ceramics (BaHf0.1MnxTi0.9-xO3, where x = 0, 0.02, 0.05, 0.08, and 0.1) are prepared by means of a sol-gel method. The microstructures, dielectric properties and ferroelectric properties of the ceramics are investigated. X-ray diffraction patterns indicate that Mn4+ ions enter the unit cell to maintain the perovskite structure of solid solution. Consequently, the tetragonality gradually decreases with increased Mn content. The grains of Mn-doped BaHf0.1Ti0.9O3 ceramics become uniform and almost spherical. The diffuseness constant decreases from 1.89 to 1.48 with increased Mn content from 0 at.% to 5 at.%. Hysteresis loops can be observed in all samples from 30 C to 90 C, which may be due to the relaxor ferroelectric property of these ceramics. (orig.)