Dielectric properties of Bi2(Zn1/3Nb2/3)2O7 electroceramics and thin films

Dielectric response of Bi2(Zn1/3Nb2/3)2O7, BiZN, ceramic materials and thin films were examined, for the first time, compared directly using terahertz (THz) spectroscopy. In the preparation of the ceramic materials, the two-step process exhibits a marked advantage over the one-step process in that the ceramic materialʹs characteristics are relatively insensitive to the sintering parameters. The ceramic materials can achieve high density (7.2 g/cm3), large dielectric constant (K=67), high quality factor (Q×f ≅80,000 GHz) and small temperature coefficient of resonance frequency (τf ≅−6 ppm/°C), when processed at optimized sintering temperature (1050°C, 4 h). Crystalline BiZN thin films, can be easily obtained when the films were in-situ deposited at high enough substrate temperature 450–600°C (30 min). The dielectric constant of BiZN thin films in THz frequency regime, ε′f·THz=32, is markedly smaller than the ε′b·THz value of BiZN bulk materials, and the quality factor of the thin films is less than 20% of the bulk materials.