Phase Transitional Behavior and Electrical Properties of Sr 2 K 0.1 Na 0.9 Nb 5− x Ta x O 15 Ceramics

Lead‐free Sr 2 K 0.1 Na 0.9 Nb 5− x Ta x O 15 ceramics were prepared using the conventional mixed‐oxide method. The phase transition corresponding to the tetragonal ferroelectric (4 mm ) to paraelectric (4/ mmm ) phase was observed with increasing x according to the XRD and dielectric properties results. Ta 5+ substitution for Nb 5+ inhibited the grain growth and also prevented the abnormal grain growth behavior. The dielectric and ferroelectric properties of the ceramics decreased and even vanished with increasing Ta 5+ substitution. Besides, the underlying mechanism for variations of the structures and properties due to Ta 5+ substitution was explained in this work.