Large electric field-induced strain and large improvement in energy density of bismuth sodium potassium titanate-based piezoelectric ceramics

• Main Authors: Supalak Manotham, Pichitchai Butnoi, Pharatree Jaita, Nitish Kumar, Komsanti Chokethawai, Gobwute Rujijanagul, David P. Cann
• Format: Journal
• Published: 2018
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85039841145&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/43821
• Institution: Chiang Mai University

© 2017 Elsevier B.V. Ceramic solid solutions based on (1-x)Bi 0.5 (Na 0.84 K 0.16 ) 0.5 TiO 3 -xBa(Nb 0.01 Ti 0.99 )O 3 or (1-x)BNKT-xBNbT) (where x = 0, 0.01, 0.03, 0.05 and 0.07 mol fraction) were investigated to demonstrate the improvement of electrical properties as compared to the unmodified BNKT ceramic. The dielectric, ferroelectric, piezoelectric and electric field-induced strain properties were investigated as a function of composition and temperature. All ceramics presented a single phase perovskite structure. X-ray diffraction analysis revealed a transition from co-existing rhombohedral-tetragonal phases to a single tetragonal phase for compositions with x > 0.03. The maximum dielectric constant tended to increase with increasing BNbT content and the dielectric spectra for all compositions exhibited a broad maximum around T d and T m . The polarization hysteresis measurement indicated a disruption in the long range ferroelectric order at the critical composition of x = 0.03 along with a significant enhancement in the electric field-induced strains (S max = 0.41%) with a large normalized strain coefficient (d * 33 = S max /E max ) of 683 pm/V. The x = 0.03 composition also presented a high energy density (0.67 J/cm 3 ) as compared with the unmodified BNKT composition (0.25 J/cm 3 ). These results suggest that the (1-x)BNKT-xBNbT solid solution is a promising lead-free piezoelectric material candidate.