Low-temperature preparation of ferroelectric Ba/sub 2/NaNb/sub 5/O/sub 15/ thin films by pulsed laser deposition

Ferroelectric Ba/sub 2/NaNb/sub 5/O/sub 15/ (BNN) thin films were prepared on MgO (100) substrates by pulsed laser deposition method. When the laser power density and repetition frequency were fixed at 200 mJ/cm/sup 2/ and 5 Hz, respectively, the c-axis oriented BNN thin film was obtained at substrate temperature of 650/spl deg/C. The interface between the c-axis oriented BNN thin film and MgO substrate was very smooth. The band gap of the c-axis oriented BNN thin film was about 3.1 eV, which accords to that of the BNN single crystal.