Phase diagrams and in-plane anisotropic misfit strains of (110) Ba0.6Sr0.4TiO3 thin films grown on (001) orthorhombic NdGaO3 substrate

Using Landau-Devonshire(LD)-type phenomenological model, we investigate the phase diagrams and in-plane anisotropic misfit strains of single-domain single-crystal (110) Ba0.6Sr0.4TiO3 film epitaxially deposited on (001) NdGaO3 substrate. Investigation indicates that film thickness plays a crucial role on formation of in-plane anisotropic misfit strains and stable phases. As is consistent with results of experiment that anisotropic strains have greatly changes with increase of film thickness. The anisotropic strains induce tetragonal phases which only contain in-plane spontaneous polarization component. These phases do not exist in BST films of the same composition under isotropic strains. Moreover, calculation manifests that anisotropic in-plane misfit strains are almost completely relaxed when film thickness is larger than 600nm, which has been reported in experiment.

[1]  A. Safari,et al.  Misfit strain relaxation in (Ba0.60Sr0.40)TiO3 epitaxial thin films on orthorhombic NdGaO3 substrates , 2006 .

[2]  M. J. E. Ulenaers,et al.  Nanosecond switching of thin ferroelectric films , 1991 .

[3]  Chen Gao,et al.  Electro-optic measurements of the ferroelectric-paraelectric boundary in Ba1−xSrxTiO3 materials chips , 2000 .

[4]  A. Tagantsev,et al.  Effect of mechanical boundary conditions on phase diagrams of epitaxial ferroelectric thin films , 1998 .

[5]  S. Alpay,et al.  Dielectric tunability of (110) oriented barium strontium titanate epitaxial films on (100) orthorhombic substrates , 2006 .

[6]  U. Böttger,et al.  Effect of anisotropic in-plane strains on phase states and dielectric properties of epitaxial ferroelectric thin films , 2005 .

[7]  James S. Speck,et al.  DOMAIN CONFIGURATIONS DUE TO MULTIPLE MISFIT RELAXATION MECHANISMS IN EPITAXIAL FERROELECTRIC THIN FILMS. I: THEORY , 1994 .

[8]  A. Safari,et al.  In-plane microwave dielectric properties of paraelectric barium strontium titanate thin films with anisotropic epitaxy , 2005 .

[9]  Y. Tomita,et al.  Preparation and characteristics of pyroelectric infrared sensors made of c‐axis oriented La‐modified PbTi03 thin films , 1987 .

[10]  A. Krauss,et al.  Composition-control of magnetron-sputter-deposited (BaxSr1−x)Ti1+yO3+z thin films for voltage tunable devices , 2000 .

[11]  A. Safari,et al.  Anisotropic strain relaxation in (Ba0.6Sr0.4)TiO3 epitaxial thin films , 2005 .