Patent ID: 7087186

Claim:
A ferroelectric/paraelectric material for use in tunable devices, having the following general formula I: AB y Ti 1-y+Δ O 3 I wherein A is one or more divalent (2 + ) ions selected from the group consisting of Ba, Sr, Ca, and Pb; B is one or more trivalent (3 + ) ions selected from the group consisting of Al, Ga, In, Sc, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Y, and Lu, paired with one or more pentavalent (5 + ) ions selected from the group consisting of Sb, Ta, Nb and V; or B is one or more divalent (2 + ) ions selected from the group consisting of Zn, Mg, and Ca, paired with one or more hexavalent (6 + ) ions selected from the group consisting of W, and Mo; or B is a combination of said 3 + and 5 + ions paired with said 2 + and 6 + ions such that charge compensation is maintained; 0<y<1, and 0<Δ≦0.2 and represents addition of excess titanium; with the provisos that 1) A cannot be Ca by itself; 2) when A is Pb and B is Mg paid with W, y<0.30 or 3) when A is a combination of Pb and at least one of Ba, Sr and Ca, the amount of Pb is less than 80% of A; and wherein said material is a pseudo ternary or higher system in the form of a single phase solid solution of a perovskite having a crystalline structure with charge balanced constituents.