Temperature Dependent Piezoelectric and Pyroelectric Response of Nb Doped (Na0.41 K0.09 Bi0.5) TiO3 Ceramics

• Published in: 2022 IEEE International Symposium on Applications of Ferroelectrics (ISAF) pp. 1 - 4
• Main Authors: Sharma, Ankur, Yadav, Pinki, Sajith, B.K., Bhatt, R., Bhaumik, Indranil, Singh, Gurvinderjit, Kaul, R.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 27-06-2022
• Subjects: Ceramics; Energy harvesting; Lead; lead-free ceramic; piezoelectricity; pyroelectricity; Rectifiers; Temperature dependence; Temperature distribution; Temperature measurement
• ISSN: 2375-0448
• DOI: 10.1109/ISAF51494.2022.9870141

In the present study, temperature dependence of the piezoelectric and pyroelectric coefficients of niobium (Nb) doped (\left.\mathrm{Na} 0.41 \mathrm{~K}_{0.09} \mathrm{Bi}_{0.5}\right) \mathrm{TiO}_3 [NKBT] ceramics has been investigated. The piezoelectric charge coefficient \left(d_{31}\right) and electromechanical coupling coefficient \left(k_{\mathrm{p}}\right) increase gradually with temperature till close to the depolarization temperature and thereafter fall sharply. The highest piezoelectric coefficients were obtained for \mathrm{x}=0.005(0.5 at. %Nb) which are d_{33} \sim 185 \mathrm{pC} / \mathrm{N}, d_{31} \sim 51 \mathrm{pC} / \mathrm{N} and \mathrm{k}_{\mathrm{p}} \sim 0.35 at room temperature. Like the piezoelectric response, the pyroelectric coefficient also shows an anomaly in the vicinity of T d . At room temperature the pyroelectric coefficient \left(p_3\right) is in the range of 2-10 \mathrm{nC} / \mathrm{cm}^2 \mathrm{~K} for all the compositions. The maximum value of p 3 observed near T d is 4.6 \mu \mathrm{C} / \mathrm{cm}^2 \mathrm{~K}. The measurements reveal the lowering of T d with increase in Nb content which can be explained on the basis of donor type behavior of niobium \left(\mathrm{Nb}^{5+}\right) ion. For energy harvesting, the generated output voltage shows maximum value for a periodic temperature oscillation of \Delta \mathrm{T} \sim 15 \mathrm{~K} at \mathrm{dT} / \mathrm{dt} \sim 0.44 \mathrm{~K} / \mathrm{s} for sample with \mathrm{x}=0.005. The study suggests that by using a proper rectifier circuit a pulsating DC output with maximum voltage of \sim 3 \mathrm{~V} can be obtained.