Phase Diagram for the 0.4Pb(Ni 1/3 ,Nb 1/3 )O 3 –0.6Pb(Zr,Ti)O 3 Solid Solution in the Vicinity of a Morphotropic Phase Boundary

A phase diagram based on dielectric‐permittivity‐versus‐temperature measurements and high‐temperature X‐ray diffractometry was proposed for 0.4Pb(Ni 1/3 ,Nb 1/3 )O 3 ‐ x PbZrO 3 ‐(0.6‐ x )PbTiO 3 (0.2 lessthan equal to x lessthan equal to 0.32) relaxor‐ferroelectric solid solution, and a morphotropic phase boundary that sharply bends toward zirconium‐rich compositions was found. A spontaneous normal‐to‐relaxor ferroelectric transition was also observed when heating was performed for all the compositions tested near the morphotropic phase boundary. Additional considerations about previously published phase diagrams for Pb(Zn 1/3 ,Nb 2/3 )O 3 ‐PbTiO 3 and Pb(Mg 1/3 ,Nb 1/3 )O 3 ‐PbTiO 3 might lead to an extension of the presented diagram to these compositions.