Plasma electrolytic deposition on aluminum tubes

High quality Ba(Zr0.2Ti0.8)O-3 (BZT) thin films were epitaxially grown on MgO single-crystal substrates. No structural phase transition took place in the temperature range of 80-300 K, and the films displayed a typical behavior of relaxor ferroelectrics, which was demonstrated by micro-Raman spectroscopy. Frequency and temperature dependence of dielectric properties was systematically investigated for the BZT thin films. It was found that enhanced dielectric properties could be obtained over a wide frequency and temperature range. This is of great importance for practical microelectronic device applications. At room temperature, a high dielectric tunability of nearly 50% was achieved over the whole measurement frequency range of 10 kHz-1 MHz by applying an electric field with intensity as low as 40 kV/cm; meanwhile, a relatively low dielectric loss was obtained and the value could be further reduced significantly with the applied dc electric field, indicating an excellent figure of merit and promising applications in tunable microwave devices for the BZT films.