Influence Of Oxygen Partial Pressure On The Structural And Dielectric Properties Of Ba(zr_(0.3)ti_(0.7))o_3 Thin Films Grown On (laalo_3)_(0.3)(sr_2altao_6)_(0.35) (001) Using Pulsed Laser Deposition

摘要

Epitaxial Ba(Zr_(0.63)Ti_(0.7))O_3 thin films were grown on (LaAlO_3)_(0.3)(Sr_2AlTaO_6)_(0.35) (001) single-crystal substrates by pulsed laser deposition at 700 ℃ in different oxygen partial pressures ranging from 6.7 Pa to 40.0 Pa. A strong correlation is observed between the structure and dielectric properties for the Ba(Zr_(0.3)Ti_(0.7))O_3 thin films. The tetragonal distortion (ratio of in-plane and out-of-plane lattice parameter, a/c) of the films depends on the oxygen partial pressures, a/c varies from 0.989 at 6.7 Pa to 1.010 at 40.0 Pa. indicating the in-plain strain changes from compressive to tensile. The in-plain strain (either compressive or tensile) shifts the Curie temperature of the Ba(Zr_(0.3)Ti_(0.7))O_3 thin films dramatically. Surface morphology and dielectric properties of Ba(Zr_(0.3)Ti_(0.7))O_3 thin films have a strong dependence of the oxygen partial pressure. The film grown 26.7 Pa. which corresponds to a moderate in-plain tensile strain and a Curie temperature of-30 ℃, shows the largest relative permittivity, tunability and the best figure of merit in a broad frequency range (1 kHz-500 MHz), which may be a promising candidate for room-temperature microwave device applications.