Characterization of Ba(Mg1/3Ta2/3)O3 and Bi2(Zn1/3Nb2/3)2O 7 microwave dielectrics in optical and microwave frequency regions

Ba(Mg_1/3Ta_2/3)O₃, BMT, and Bi₂(Zn_1/3Nb_2/3)₂O₇ , BiZN, thin films were grown on [100] MgO single crystal substrates using pulsed laser deposition process. The high-frequency dielectric properties of thus obtained thin films were measured using optical transmission spectroscopy. Characteristics of BMT thin films were compared with those of BiZN thin films. BMT films need higher substrate temperature (~800°) and longer deposition time (~75 min) than those of BiZN thin films for getting better crystallinity. The index of refraction n and the absorption coefficient k of these films derived from their optical transmission spectra reveal that both optical parameters (n, k) for the BMT films are smaller than those of BiZN films. These behaviors are intimately correlated with lower microwave dielectric constant K and higher quality factor Q×f characteristics for BMT bulk materials, as compared with those of BiZN bulk materials