Strain-induced anisotropy in microwave dielectric properties of (Ba,Sr)TiO3 thin films with directly applied uniaxial ⟨100⟩ stress -: art. no. 242904

The microwave dielectric properties and their change with applied uniaxial < 100 > stress in an epitaxially deposited Ba0.6Sr0.4TiO3 thin film on (001) MgO have been measured as a function of dc bias (0 to +/- 40 V) and frequency (1-20 GHz). A significant increase in the relative dielectric constant (from 480 to 530) is observed when uniaxial stress is applied. Similarly, the dielectric tuning of the film at an applied electric field of 4x10(4) V/cm increases from 43% to 48% at 10 GHz. These increases correspond to an extremely small increase of the in-plane lattice parameter of the film, a, from 3.965 to 3.967 A, (i.e., similar to 0.05%) due to the applied uniaxial tensional stress.