Dielectric properties of (Ba/sub 0.60/,Sr/sub 0.40/)TiO/sub 3/ thin films on NdGaO/sub 3/ substrates at 10 GHz

This work investigates the effects of anisotropic epitaxial strains on the microwave frequency dielectric response of BST (60/40) thin films. Dielectric properties such as permittivity and tunability along the <-110>, <-111> and <001> crystallographic directions correlate well with the variation of elastic strain energy as a function of film thickness. We demonstrate unequivocally that the maximum permittivity and tunability is obtained along a crystallographic direction where the strain is a minimum.