Alkoy, Ebru Mensur2024-07-122024-07-1220100021-897910.1063/1.35038452-s2.0-78649279461https://dx.doi.org/10.1063/1.3503845https://hdl.handle.net/20.500.12415/8136Lead-free, dense, 1 mol % CuO-added potassium sodium niobate K0.5Na0.5NbO3 (KNN) fibers were successfully drawn using a novel alginate gelation technique. Piezocomposites with 1-3 connectivity were prepared with an epoxy matrix with various fiber volume fractions (V-f). Electrical properties of the piezocomposites were investigated and compared with bulk KNN ceramics of the same composition. The dielectric constant of the piezocomposites were found to increase from 67 to 191 with the addition of CuO into KNN and increasing V-f in the piezocomposite. A constricted, antiferroelectriclike double hysteresis polarization versus electric field (P-E) loop was observed in bulk KNN. A large and fully recoverable electrostrain of 0.07% was measured for bulk KNN and 0.03% for the piezocomposites under an electric field of 50 kV/cm, respectively. The double hysteresis P-E loop and the recoverable nature of the electrostrain was due to the Cu'''(Nb)-V-O(center dot center dot) defect dipoles creating an internal field that restores the original domain pattern when the field is removed. A very high electrostrictive Q(33) coefficient of 35.6 X 10(-3) m(4)/C-2 and an even higher Q(33) of 162 X 10(-3) m(4)/C-2 was obtained for bulk KNN and piezocomposites, respectively. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3503845]eninfo:eu-repo/semantics/closedAccessArticle9Q2108WOS:000284270900105Q2