Solid Solutions Based on Ferroelectric PbNb ₂ ,O ₆

Abstract

An X‐ray and dielectric study of three series of PbNb 2 O 6 ‐type solid solutions was carried out. The PbNbZOs‐type phase was present up to the following limits: (1) (Pb 1−x Bi 4 / 3x )(Ti x Nb 2 ‐ x .)O 6 , ×= 0.2; (2) (Pb l ‐ x Bi 4 3 x )(Ti 2 Nb l —2) 2 0 6 , ×= 0.2; and (3) (Pb 1−x Bi 2 / 3x )Nb 2 O 6 ×= 0.3. Orthorhombic distortion b/a and Curie temperature decreased with increasing x. Bi 4/3 ‐Ti 2 0 6 was most effective in this respect and Bi 2 , 3 ‐Nb 2 O 6 had the least influence. The important role played by ions of different valency located on crystallographically equivalent sites is pointed out.