Dielectric nonlinear behavior of (Ba _0.95 Ca _0.05 )(Ti _0.83 Zr _0.17 )O ₃ ‐based multi‐layer ceramic capacitor

Abstract

Abstract The influence of temperature on the variation in dielectric nonlinearity and domain structures was investigated for the (Ba 0.95 Ca 0.05 )(Ti 0.83 Zr 0.17 )O 3 ( BCTZ )‐based multilayer ceramic capacitor that shows a diffuse phase transition. Whereas the dielectric constant (ε r ) vs temperature shows a broadened maximum peak at low ac driving field, such a peaked behavior disappears at high ac driving field due to an abrupt increase in dielectric constants at low temperatures. Such low temperature effect can be associated with an enhanced spontaneous polarization ( P S ) and a significant increase in irreversible domain wall contribution to polarization representing normal ferroelectric behavior based on the Preisach analysis. No ferroelectric domain contrasts were observed at room temperature through transmission electron microscopy. However, they appeared and became more and more distinct with the decrease in temperature, and the crystal structure also changed from cubic to rhombohedral with increased lattice constants. It demonstrates that the dramatic increase in the dielectric nonlinearity with decreasing temperatures originates from the corresponding changes in domain and crystal structure, where the polar‐micro‐regions of BCTZ at room temperature change to normal ferroelectric domains at low temperatures.