Direct‐Current Field Dependence of Dielectric Properties in Alumina‐Doped Barium Strontium Titanate

The dielectric properties of (Ba 0.6 Sr 0.4 )TiO 3 and Al 2 O 3 ‐doped (Ba 0.6 Sr 0.4 )TiO 3 have been characterized. The grain size of the specimen is maximum for (Ba 0.6 Sr 0.4 )TiO 3 that has been doped with 1 wt% Al 2 O 3 . The density and the real part of the relative dielectric constant each decrease as the Al 2 O 3 content increases. The loss factor is minimum for (Ba 0.6 Sr 0.4 )TiO 3 that has been doped with 2 wt% Al 2 O 3 . The dielectric constant of the specimens decreases as the applied dc field increases. The influence of the dc field on the loss factor is much less than that on the dielectric constant. The tunability is ∼24% for (Ba 0.6 Sr 0.4 )TiO 3 that has been doped with 1 wt% Al 2 O 3 .