Electrical Properties of Lead‐Barium Niobates and Associated Materials

The electrical properties of materials in the system lead‐barium niobate are described. Particularly useful materials are obtained when between 25 and 50 mole % of lead niobate is replaced by barium niobate. Materials with a 40 to 45 mole % replacement have permittivities of more than 1500 and radial electromechanical coupling coefficients of more than 0.35, but the Curie temperature is then only about 250°C, the minimum value obtained in the system. Higher Curie temperatures are accompanied by somewhat lower values of permittivity and coupling coefficient. An indication is given of the effects of several other additives on the properties of lead niobate, and it is shown that barium‐strontium niobates are only weakly ferroelectric at room temperature.