Published online by Cambridge University Press: 10 February 2011
Na0.5K0.5NbO3 films have been grown onto polycrystalline Pt80Ir20 substrates at two different regimes: high (∼ 400 mTorr) and low (∼ 10 mTorr) oxygen pressure. Films grown at high oxygen pressure have been found to be single phase and highly c-axis oriented. The concept of discriminated thermalization has been developed to explain the dynamics of the laser ablation process and to find reliable pulsed laser deposition (PLD) processing conditions. The phenomenon of self assembling of Na0.5K0.5NbO3 films along [001] direction has been observed. On the other hand, films grown at low oxygen pressure have been found to be mixed phase of ferroelectric Na0.5K0.5 NbO3 and paraelectric potassium niobates. Superparaelectric behavior has been observed in these films: 5% tunability at electric field of 100 kV/cm, losses as low as 0.003 and excellent stability to the temperature and frequency changes.