Effect of Oxygen Partial Pressure on Structure and Dielectric Property of BaTi₂O₅ Films Prepared by Laser Ablation

Abstract

BaTi₂O₅ ferroelectric films were prepared on MgO (100) substrates by laser ablation at various oxygen partial pressures (P_O2). The effect of P_O2 on the orientation, composition, surface morphology and dielectric property of the films was investigated. The molar ratio of Ti to Ba was independent of P_O2, almost in agreement with the stoichiometric composition of BaTi₂O₅. The BaTi₂O₅ films showed the orientation of (710) and (020) depending on P_O2. At P_O2=12.5 Pa, (020) oriented BaTi₂O₅ film with an elongated granular and perpendicularly crossing texture was epitaxially grown on MgO (100) substrates. The BaTi₂O₅ film prepared at P_O2=12.5 Pa exhibited a sharp permittivity maximum (ε′≈2000) at 750 K.