Tunable, low loss Bi1.5Zn1.0Nb1.5O7∕Ba0.6Sr0.4TiO3∕Bi1.5Zn1.0Nb1.5O7 sandwich films

Bi 1.5 Zn 1.0 Nb 1.5 O 7 ∕ Ba 0.6 Sr 0.4 Ti O 3 ∕ Bi 1.5 Zn 1.0 Nb 1.5 O 7 (BZN/BST/BZN) sandwich films were deposited by radio frequency magnetron sputtering. The relative permittivity and dielectric loss of the sandwich films were measured using planar Pt∕BZN∕BST∕BZN∕Pt∕Ti∕SiO2∕Si capacitor structures. The sandwich films with thickness of about 280nm exhibited relative permittivity around 206–247 and dielectric loss tangent (tanδ) less than 0.008 at 1MHz. Films annealed at 750°C had an ∼11% relative tunability of the permittivity at a maximum applied bias field of 0.77MV∕cm. The sandwich films are not ferroelectric at room temperature.