The effect of tetragonality on direct current (dc) bias characteristics of BaTiO3-based MLCCs

The influence of tetragonality on direct-current (dc) bias characteristics of BaTiO
3
-based multi-layer ceramic capacitors (MLCCs) are systematically investigated. It is shown that, with the similar grain size, the permittivity of specimen was enhanced as the magnitude of saturation polarization (P
s
) decreased. Thus, it is also supposed that the tetragonality may have the remarkable influence on both the permittivitys and dc-bias characteristics under the high dc-bias. With an increase in the tetragonality, the permittivity of a high ac driving field range will decrease to a low level. In particular, the magnitude of P
s
increases with an increase of grain size under the dc-bias of 400 V/μm, which is attributed to the motion of 90° domain wall. In addition, the dependence of the domain wall configuration on dc-bias is also studied. Our studies could broaden the fundamental understanding of bias characteristics, thus opening up opportunities in improving permittivitys of BaTiO
3
-based MLCC under a high dc-bias field.