Pb 5 (Ge,Si) 3 O 11 Ferroelectrics

The compound Pb 5 Ge 3 O 11 is an optically active ferroelectric with a transition temperature near 177°C. Solid solutions containing up to 62% Si replacing Ge were prepared from the melt. Increasing the Si content lowers the melting point, Curie point, and coercive field. Permittivity measurements on single crystals indicate a simple second‐order phase change.