Infrared study of microwave dielectric materials Ba2Ti9O20 and Ba(Mg1/3Ta2/3)O3

[[abstract]]We study the infrared properties of Ba2Ti9O20 dealt with different annealing gas and doped with different content of SnO2 as well as Ba(Mg1/3Ta2/3)O3 with different Ni doping and with different preparation processes. And we discuss the correlation between their infrared characteristics and microwave properties. First, we obtain the following results. (i) The Ba2Ti9O20 annealed with O2 gas has maximum Q?f value and minimum dielectric constant, which represents the sample has more ordered structure and less defect. (ii)The Ba2Ti9O20 doped with 0.055 mol SnO2 has the maximum Q?f factor value. While the content of SnO2 doped with Ba2Ti9O20 exceeds 0.055 mol, the linewidths of several infrared vibration mode of the Ba2Ti9O20 become larger. Due to the descent of the coherency in lattice vibration modes for Ba2Ti9O20 sample, the Q?f value degrades. Moreover, we find that the vibration mode Eu(II) at about 241 cm-1 of the Ba(Mg1/3Ta2/3)O3 has maximum spectral weight of the optical conductivity. And the linewidth of this vibration mode sensitively gauges the Q?f value. When the Q?f value of the Ba(Mg1/3Ta2/3)O3 which is doped with different Ni content or which is dealt with different preparation processes degrades, then the linewidth of this vibration mode increases, which means the coherency of lattice vibration modes degrades (the 1:2 ordering degree degrades).