| Abstract Scope |
The Pb(Mg,Nb)O3-PbTiO3 (PMN-PT)-based relaxor ferroelectrics are able to show superior piezoelectric properties. However, in our experiments on PMN-PT ceramics for energy harvesting applications, an uncertainty that does not guarantee replicability of these superior properties was identified, especially for the factor of piezoelectric energy harvesting figure of merit (FOM). This work reveals the links and unlinks of the stoichiometry, phase and microstructure to the piezoelectric properties, especially for the energy harvesting figure of merit (FOM). The results show that the formation of a monoclinic phase, P1m1, is responsible for the large permittivity and d33 (longitudinal piezoelectric charge coefficient), and thus for the 90 % higher FOM values than those in literature. On the other hand, another monoclinic phase, C1m1, as well as a coexisting tetragonal secondary phase, suppresses the development of d33 and hence degrades the FOM by over 60 %. This phase uncertainty caused the irreproducible FOM values. |