Effect of laser energy density on the fabrication of Ba2NaNb5O15 thin films by pulsed laser ablation

Ferroelectric thin films of barium sodium niobate, Ba2NaNb5O15 (BNN), were prepared on Pt substrates by pulsed laser ablation at O-2 gas pressures of 0.01 and 0.1 Torr. We examined the effect of laser energy density on the fabrication of BNN thin films. The laser energy density was changed from 1.67 J/cm(2) to 5.0 J/cm(2). On increasing laser energy density, the chemical composition of thin films approached the BNN stoichiometry. Crystallinity of BNN thin films fabricated at higher laser energy densities developed a tendency to orient along the c-axis. Thin films of BNN deposited at an O-2 gas pressure of 0.1 Torr and a laser energy density of 5.0 J/cm(2) have a stoichiometoric composition and a prominent c-axis orientation with a remanent plarization P-r of 0.8 mu C/cm(2) and a coercive field E-c of 24.0 kV/cm at room temperature.