Ba(Pb1-xSnx)O-3, Ba(Pb1-xCex)O-3, (Ba1-yLay)(Pb0.7Sn0.3)O-3 (0 < y < 0.25).
(Ba1-yLay)(Pb0.75Ce0.25)O-3 (0 < y < 0.3), and (Ba0.85La0.15)(Pb1-xCex)O-3
(0 <x < 0.3) solid solutions were prepared by solid-state reactions. In th
e first three systems, a metal-insulator transition was identified.