Effect of Dy on the dielectric nonlinear behavior of Mn and V-doped BaTiO 3 multilayer ceramic capacitors
- PDF / 627,614 Bytes
- 9 Pages / 584.957 x 782.986 pts Page_size
- 13 Downloads / 217 Views
The effect of Dy-doping on the dielectric nonlinearity was investigated in Mn and V-doped BaTiO3 multilayer ceramic capacitors under the same grain size condition, which was described by the Preisach model utilizing the first order reversal curve (FORC) distribution. The dielectric constants in both low and high field region could be enhanced by the Dy-doping, and it was associated with the increase of both reversible and irreversible FORC distributions near zero bias, whereas there was little variation in the saturation polarization that scales to the magnitude of spontaneous polarization. These results demonstrate that both reversible and irreversible domain wall motions are enhanced by Dy-donor incorporation in BaTiO3 resulting in softening of the dielectrics and increase of dielectric constants, which is supposed to be caused by the decrease of the pinning sources such as defect dipoles formed by the oxygen vacancies and their interaction with the domain walls.
I. INTRODUCTION
To increase the capacitance and volume efficiency of BaTiO3-based base metal electrode (BME) multilayer ceramic capacitors (MLCC), the dielectrics having a high-dielectric constant are more and more required. One of the simplest methods to enhance the dielectric constant is to increase the grain size.1–5 However, the increase of grain size causes many side effects in the dielectric properties, such as an inferior dc-bias characteristic, that is, an abrupt decrease of dielectric constant by the application dc-field, and a high-aging rate, that is, a steep decrease of the dielectric constant by the lapse of time. Thus, ideally the dielectric constant should be increased without increasing the grain size. In spite of the extensive studies for the grain size effect on the dielectric constant,1–5 however, those reports that studied the factors which influence the dielectric constant under the same grain size condition are very limited. Recently, it was reported that the dielectric constant can change significantly even under the same grain size condition in the submicron range depending on the excess Ba concentration in the additives that influences the A/B nonstoichiometry in the ABO3 structure.6 The dopant incorporated ABO3 structure can change from A-site deficient to stoichiometric and then B-site deficient ABO3 depending on Ba concentration in additives, and
Contributing Editor: Ian M. Reaney a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2015.219 J. Mater. Res., Vol. 30, No. 16, Aug 28, 2015
the Ba concentration of the maximum dielectric constant corresponds to the stoichiometric ABO3 structure with A/B ratio being 1. This behavior can be correlated with the reported phenomena of BaTiO3 that the tetragonality and the magnitude of the spontaneous polarization under the same particle size condition are maximum when the Ba/Ti ratio is 1 and decrease when the ratio deviates from 1.7 It has been reported that donor-doped Pb(ZrxTi1x)O3 (PZT) ceramics show much higher levels of domain wall motion
Data Loading...
