Dielectric properties of Bi-2(Zn1/3Nb2/3)(2)O-7 electroceramics and thin films

Dielectric response of Bi-2(Zn1/3Nb2/3)(2)O-7, BiZN, ceramic materials and thin films were examined, for the first time, compared directly using terah ertz (THz) spectroscopy. In the preparation of the ceramic materials, the t wo-step process exhibits a marked advantage over the one-step process in th at the ceramic material's characteristics are relatively insensitive to the sintering parameters. The ceramic materials can achieve high density (7.2 g/cm(3)), large dielectric constant (K = 67), high quality factor (Qxf cong ruent to 80,000 GHz) and small temperature coefficient of resonance frequen cy (tau (f) congruent to 6 ppm/degreesC), when processed at optimized sinte ring temperature (1050 degreesC, 4 h). Crystalline BiZN thin films, can be easily obtained when the films were in-situ deposited at high enough substr ate temperature 450-600 degreesC (30 min). The dielectric constant of BiZN thin films in THz frequency regime, (epsilon ')(f).(THz)= 32, is markedly s maller than the (epsilon ')(b).(THz) value of BiZN bulk materials, and the quality factor of the thin films is less than 20% of the bulk materials. (C ) 2001 Elsevier Science Ltd. All rights reserved.