Synthesis and electrical properties of sodium bismuth niobate Na0.5Bi2.5Nb2O9

Abstract The crystal structure of Na 0.5 Bi 2.5 Nb 2 O 9 was refined from its powder X-ray diffraction (XRD) data. Sodium bismuth niobate at 23 °C is orthorhombic, A 2 1 am , with a =5.4998(3) A, b =5.4602(2) A, c =24.952(1) A, and Z =4. The piezoelectric properties were investigated using the dense bulk ceramics. The electromechanical coupling coefficients ( k ij ) and electrical quality factors ( Q m ) are k 31 =3.2%, k t =10.0%, and Q m =3800. Single crystals were also grown from stoichiometric melts using a slow cooling technique. The dielectric and ferroelectric properties of the crystal indicates that a spontaneous polarization clearly occurs in the crystallographic a – b plane.