Room-temperature tunable microwave properties of strained SrTiO3 films

Abstract

Structural distortion of ferroelectric thin films caused by film strain has a strong impact on the microwave dielectric properties. SrTiO3 thin films epitaxially grown on (110)DyScO3 substrates using molecular beam epitaxy are extremely strained (i.e., ∼1% in-plane tensional strain) from 3.905Å of bulk SrTiO3. The room-temperature in-plane dielectric constant and its tuning of the films at 10GHz are observed to be 6000 and 75% with an electric field of 1V∕μm, respectively. The control of strain in SrTiO3 provides a basis for room-temperature tunable microwave applications by elevating its phase-transition peak to room temperature.