Effect of niobium on electrical properties of Sr0 center dot 8Bi2 center dot 3(Ta1-xNbx)(2)O9+alpha thin films processed by sol-gel method

Polycrystalline SBTN ferroelectric thin films were prepared by the sol-gel method with various Nb mole ratios on Pt/SiO2/Si(100) substrates, The films were annealed at different temperatures and characterised in terms of phas e and microstructure, A relatively well saturated hysteresis pattern was ob tained at x=0.2 in Sr0.8Bi2.3 (Ta1-xNbx)(2)O9+a thin films. At an applied v oltage of 5 V, the dielectric constant epsilon (r) and dissipation factor t an delta of a typical Sr0.8B2.3(Ta1-xNbx)(2)O9+a thin film (x=0.2) were abo ut 236.2 and 0.034. Measured remanent polarisation 2P(r) and coercive field E-c were 4.28 muC cm(2), and 38.88 kV cm(1) respectively. No fatigue was o bserved up to 6 x 10(10) switching cycles at 5 V and the normalised polaris ation reduced by a factor of only 4%. MST/4730.