The influence of oxygen vacancies on piezoelectricity in samarium‐doped Pb(Mg_1/3Nb_2/3)O₃‐PbTiO₃ ceramics

Abstract

A study of 0.71Pb(Mg1/3Nb2/3)O3‐0.29PbTiO3 shows that, when it is doped with 2.5% Sm on the A‐site, in addition to an almost threefold increase in piezoelectric charge coefficient and dielectric permittivity, there is a 2 order of magnitude reduction in conductivity, attributed to a decrease in oxygen vacancy concentration. An analysis of the nonlinearity of permittivity with respect to field amplitude shows that both the reversible and irreversible contributions increase significantly with Sm‐doping, with simple models showing that these changes are consistent with a reduction in the concentration of dipolar defects that can inhibit both polarization rotation and domain wall translation. Contrary to the argument that doping increases heterogeneity, there is little change in the diffuseness of the peak in permittivity as a function temperature, whilst there is a 15% increase in spontaneous polarization with Sm addition. Through comparison of the Rayleigh law parameters with those published for other piezoelectric materials, it is concluded that a significant contribution to the observed increase in piezoelectric performance due to Sm‐doping of PMN‐PT is similar in origin to that seen in soft, donor‐doped PZT and other conventional piezoelectric ceramics.

Recent Developments on Relaxor-PbTiO3 Ferroelectric Crystals

“…The donor-dopant La 3+ in PZT has been intensively studied because it increases the dielectric constant due to relaxor behavior and is suitable for electro-optical applications [137][138][139][140][141]. Sm 3+ has recently drawn attention due to its contribution to a giant electromechanical coupling factor and drastic increase of the piezoelectric coefficient in relaxor-PT systems [142][143][144][145][146][147][148][149][150]. A certain addition of Sm dopant is confirmed to lead to the highest values of d 33 , being on the order of 1500 pC N −1 , and ε T 33 /ε 0 being on the order of 13,000 in PMN-PT ceramic, and d 33 being on the order of 4100 pC N -1 and ε T 33 /ε 0 of ~12,000 in PMN-PT single crystal, respectively [24,146].…”

Sm and Mn doped enhancing the electrical properties of .68PMN–.32PT relaxor ferroelectric thin films

“…Li et al. have proved the Sm 3+ substitute Pb 2+ at the A site can reduce the oxygen vacancy concentration, thereby improving the dielectric and ferroelectric properties 11,12,15–19 . On the other hand, Mn‐doped can refine the grains, decrease the leakage current, and improve the remanent polarization 20–24 .…”

“…14 Li et al have proved the Sm 3+ substitute Pb 2+ at the A site can reduce the oxygen vacancy concentration, thereby improving the dielectric and ferroelectric properties. 11,12,[15][16][17][18][19] On the other hand, Mn-doped can refine the grains, decrease the leakage current, and improve the remanent polarization. [20][21][22][23][24] Therefore, appropriate addition of Sm 3+ and Mn 2+ can effectively inhibit the formation of oxygen vacancies in PMN-PT films, thereby reducing the leakage current and improving the quality of films.…”

Samarium-Doped Lead Magnesium Niobate-Lead Titanate Ceramics Fabricated by Sintering the Mixture of Two Different Crystalline Phases

“…Recently, Li et al reported a PMN-PT ceramic with ultrahigh piezoelectric coefficients (d 33 ) of up to 1500 pC/N and dielectric permittivity (ε 33 /ε 0 ) of above 13,000 via the doping of samarium [18]. Due to the unexpectedly high piezoelectric response in Pb-based ferroelectrics, rare earth element doping modification has recently attracted much attention in modifying piezoelectric ceramics [19][20][21][22][23][24].…”