Low temperature dielectric characterization of Mg-doped SrTiO3 thin films prepared by sol-gel

Voltage dependence of dielectric constant ε′ of ferroelectrics and low dielectric loss tan δ of incipient ferroelectrics make them attractive for tuning elements in microwave circuits. In this letter, field dependence of the low-temperature dielectric permittivity and polarization of Mg-doped SrTiO3 films is studied. Incorporation of Mg on both Sr and Ti sites decreases the ε′ and relative tunability nr of sol-gel derived SrTiO3 films, whereas polarization is reduced by Ti site substitution only. tan δ of the studied films is ≤0.012, decreasing at low temperatures down to 0.001 when Ti is substituted by 5% of Mg.