An Advanced Ferroelectric Properties of the Mn Doped Na_0.5Bi_4.5Ti₄O₁₅ Ceramics Fabricated by Hot-Forging Method

Mn doped Na_0.5Bi_4.5Ti₄O₁₅ (NBTM) ceramics were fabricated by ordinary firing (OF) and hot forging (HF) method. The HF(//) sample is strongly oriented to the c-axis which is confirmed by the X-ray diffraction. Dielectric constant of HF(⊥) sample at Curie temperature is about 5176 which is larger than that (416) of the HF(//) sample. The value of the remnant polarization P_r and coercive field E_cof HF(⊥) samples at 200°C are 17.8 μC/cm² and 28.5 kV/cm, respectively. From the temperature dependence of conductivity, the activation energy of the HF(⊥) sample is 1.65 eV in the temperature range of 520°C ∼750°C.

Keywords:

• Na_0.5Bi_4.5Ti₄O₁₅ ceramics
• hot forging
• hysteresis loop

Acknowledgment

“This research was supported by a grant from ‘Center for Advanced Materials Processing’ of ‘21st Century Frontier R&D Program’ funded by the Ministry of Science and Technology, Republic of Korea.”

Paper originally presented at AMF-4, Bangalore, India, December 12–15, 2003; received in final form April 10, 2005. The original Proceedings of the Fourth Asian Meeting on Ferroelectricity (AMF-4) are published in seven earlier volumes of FERROELECTRICS (Volumes 323–329, inclusive).