Near single crystal-level dielectric loss and nonlinearity in pulsed laser deposited SrTiO3 thin films

We present low-frequency dielectric loss and nonlinearity measurements in ${\mathrm{SrTiO}}_{\mathrm{3}}$ thin films grown by pulsed laser deposition on ${\mathrm{SrRuO}}_{\mathrm{3}}$ electrode layers. A low loss tangent in the order of ${10}^{\text{−4}},$ close to the level found in ${\mathrm{SrTiO}}_{\mathrm{3}}$ single crystals, was observed. Combined with a large tunability, this resulted in a figure of merit for frequency and phase agile materials that can rival that observed in single crystals. The result is potentially significant for tunable microwave device applications, and it points to stress and interface effects as the possible causes for higher dielectric losses in thin films.