Effect of Acceptor and Donor Dopants on the Dielectric and Tunable Properties of Barium Strontium Titanate

The effects of different concentrations of Mn 2+ , Mg 2+ , Al 3+ , Fe 3+ , La 3+ , and Nb 5+ on the dielectric and tunable properties of Ba 0.6 Sr 0.4 TiO 3 ceramics were investigated. It was found that doping in small amounts with acceptor ions such as Mg 2+ , Fe 3+ , and Al 3+ could meliorate the dielectric properties clearly. Decrease of dielectric loss was attributed to the formation of compensating defects originating from acceptor substitution. It was concluded that the tunability was linked to both the dielectric constant and the grain size. A higher figure of merit was obtained by doping the ceramics with smaller ions of Al and Fe, compared to Ti.