Ca2+ doping effects in (K, Na, Li)(Nb0.8Ta0.2)O3 lead-free piezoelectric ceramics

Ferroelectric and dielectric properties of Ca2+-doped and Ca2+–Ti4+co-doped K0.5Na0.5NbO3thin films

“…Hagh et al 81 reported an increase in resistivity by doping with 0.5-1.5 mol% Ba 2+ in bulk KNN, implying that Ba 2+ acts as a donor dopant in KNN. A similar effect might be expected for doping with other alkali earth metals, such as Ca 2+ , but this was not observed in the present work or in literature on bulk KNN [63][64][65] .…”

“…Ca 2+ and Ti 4+ are both non-toxic, and therefore suitable for in vivo applications 61,62 . Ca 2+ doping is reported to have a softening effect on the ferroelectric properties of bulk KNN 63 , improve dielectric properties 64 and to increase the piezoelectric coefficient (d 33 or d 33 * ) compared to undoped KNN [63][64][65][66] . Enhanced ferroelectric performance has been reported for bulk KNN doped with 0.55, 1 and 5 mol% CaTiO3 [67][68][69][70][71] .…”

Effect of iron acceptor doping and calcium donor doping in potassium sodium niobate‐based lead‐free piezoceramics

“…The analysis of d 33 data highlights that the highest values can be achieved with 0.1-0.25 mol calcium doping, having the highest densities and room temperature ε r . Tang et al 46 reported that the remanent polarization P r becomes smaller for KNLNT-Ca samples than for KNLNT samples.…”

“…investigated [(K 0.43 Na 0.57 ) 0.94 Li 0.06 ][(Nb 0.94 Sb 0.06 ) 0.95 Ta 0.05 ]O 3 + x mol% Fe 2 O 3 (KNLNST + x Fe, x = 0–0.60) ceramics via conventional solid‐state sintering, proposing that Fe 3+ ions first occupy the A‐site at the low doping level and then at higher contents the B‐site and/or interstitials of the ABO 3 ‐type perovskite lattice 43 . Only a few results have been published on the effect of Ca 2+ doping on the dielectric properties of KNLNT ceramics 46 and KNN thin‐films 47 . We propose that alkali volatilization is most likely the major problem for making the KNN‐based material 48,49 an alternative to lead‐based piezoceramics.…”