Phase evolution and relaxor to ferroelectric phase transition boosting ultrahigh electrostrains in (1−x)(Bi1/2Na1/2)TiO3-x(Bi1/2K1/2)TiO3 solid solutions

Lead‐Free Relaxor Ferroelectric Ceramics with Ultrahigh Energy Storage Densities via Polymorphic Polar Nanoregions Design

“…[4,21] Aiming at this principle, the polymorphic polar nanoregions (PNRs) design strategy shown in Figure 1 has been adopted to develop a BNT-based ceramic dielectric with high energy storage performances. Previous studies have proved that the introduction of dopants such as Bi 0.5 K 0.5 TiO 3 , [22][23][24] BaTiO 3 [18,25,26] or SrTiO 3 [27,28] into BNT ceramics can construct the morphotropic phase boundary (MPB) and coexistence structures of micrometersize domains and polymorphic nanodomains, which effectively promoted the polarization reversal and extension owing to low energy barriers, [18] thus achieving greater electric field-induced polarization behaviors (Figure 1b). Then the long-range ferroelectric (FE) order of the matrix compositions was interrupted and relaxation behavior was enhanced via adding modifiers, decreasing the domain size to the nanoscale, the formation of polymorphic PNRs results in a small P r (Figure 1c).…”

Phase evolution and strong temperature‐dependent electrostrictive effect in (1−x)Pb(Mg1/3Nb2/3)O3‐xPbTiO3 solid solutions

“…Temperature evolutions of E c demonstrate a similar evolution law, as illustrated in Figure 7C. A huge number of macrodomains convert into short‐range order PNRs at T FR resulting in a significant fall in P r and E c 48 . The remaining P r and E c suggest that a certain volume of PNRs are still maintained in the temperature range from T m to T B due to the nature of RFEs 16 …”

“…The E pos peak moves toward the direction of the decreasing E ‐field, indicating that the long‐range order is disrupted and the material transfers from a ferroelectric to an RFE state 66 . This is accompanied by a progressive drop in S neg and the appearance of the pinched P – E loop, which is linked to an E ‐field‐induced RTF phase transition 48,66 . Finally, as the temperature rises over the third characteristic temperature T N‐dis , the values of E neg and E pos become stable and rarely vary.…”

“…A huge number of macrodomains convert into short-range order PNRs at T FR resulting in a significant fall in P r and E c . 48 The remaining P r and E c suggest that a certain volume of PNRs are still maintained in the temperature range from T m to T B due to the nature of RFEs. 16 The temperature dependency of electrostrains in PMN-xPT ceramics should also be investigated from an application standpoint.…”

“…66 This is accompanied by a progressive drop in S neg and the appearance of the pinched P-E loop, which is linked to an E-field-induced RTF phase transition. 48,66 Finally, as the temperature rises over the third characteristic temperature T N-dis , the values of E neg and E pos become stable and rarely vary. The overall current responses are very weak, and the material enters an RFE state fully.…”