In situ transmission electron microscopy study of the nanodomain growth in a Sc-doped lead magnesium niobate ceramic

Abstract

In situ transmission electron microscopy study of the nanodomain growth in a Sc-doped lead magnesium niobate ceramic AbstractSc doping enhances the B-site 1:1 cation ordering in the Pb(Mg1/3Nb2/3)O3ceramic. At low doping levels, the electrical polar domains remain at the nanometer scale and the relaxor ferroelectric behavior persists. The electric field-induced relaxor to normal ferroelectric phase transition process was directly observed with an in situtransmission electron microscopy technique in a Sc-doped Pb(Mg1/3Nb2/3)O3 polycrystalline sample. It was found that the phase transition started at the grain boundary and took two steps to complete: the gradual coalescence of the polar nanodomains and the abrupt formation of the large wedge-shaped ferroelectric domains.

Effect of uniaxial stress on ferroelectric behavior of (Bi1/2Na1/2)TiO3-based lead-free piezoelectric ceramics

“…Indeed, the P-E hysteresis loops in BNT-AFE at 140°C are very much like the ones observed in Pb͑Mg 1/3 Nb 2/3 ͒O 3 -based relaxor ferroelectric ceramics. 33 In addition, the fact that the electric field-induced transverse strain x 11 in BNT-AFE remains negative irrespective of the field polarity ͓Fig. 3͑b͔͒ is suggestive of a relaxor ferroelectric displaying an electrostrictive behavior.…”

“…30 If we assume that the ferroelectric phase in BNT-AFE possesses the same polarization as in BNT-FE, we can estimate the volume fractions of the ferroelectric and nonferroelectric phases at about 25% and 75%, respectively, in the BNT-AFE ceramic at room temperature. The electric field-induced antiferroelectric-to-ferroelectric phase transition was suggested to be responsible for the pinched P-E hysteresis loops and the large positive longitudinal strain x 33 . It is interesting to note from Fig.…”

“…Three linear variable displacement transducers were used to measure the electric field-induced strains: one for the longitudinal strain x 33 in the thickness direction, and two for the transverse strain x 11 in the radial direction. During the measurement, the signals ͑electric field E, longitudinal strain x 33 , and transverse strain x 11 ͒ were collected and recorded simultaneously with a multichannel oscilloscope.…”

“…2 These research efforts have been largely focused on ceramics based on ͑K 0.5 Na 0.5 ͒NbO 3 ͑KNN͒ and ͑Bi 1/2 Na 1/2 ͒TiO 3 ͑BNT͒, and piezoelectric coefficient d 33 values close to that of Pb-containing ceramics have been reported. [3][4][5][6][7][8][9][10][11] While d 33 is an important benchmark value in piezoelectric ceramics, it is not the decisive quantity in all applications: for actuator applications, it is often desirable to have large field-induced strain, even when the remanent polarization and correspondingly d 33 at zero field is small. We recently observed giant electric field-induced strains ͑up to 0.45%͒ in ceramics of the ͑1−x − y͒ ͑Bi 1/2 Na 1/2 ͒TiO 3 -xBaTiO 3 -y͑K 0.5 Na 0.5 ͒NbO 3 system.…”

Evolution of nanodomains during the electric-field-induced relaxor to normal ferroelectric phase transition in a Sc-doped Pb(Mg1∕3Nb2∕3)O3 ceramic

“…However, due to technical difficulties, there have been no publications on the direct observation of such evolution at the nanoscale with TEM until recently when we briefly reported the growth of polar nanodomains during a field-cooling process. 20 In the present paper, more detailed results are reported, including the macroscopic properties measurement, the polar nanodomain growth during a poling process, the response of chemical nanodomains to applied electric fields, and the interactions of the growing polar domains with the chemical cation ordered domains.…”