A perovskite lead-free antiferroelectric xCaHfO3-(1-x) NaNbO3 with induced double hysteresis loops at room temperature

Abstract

We demonstrated a new CaHfO3-NaNbO3 solid solution system that allows stable antiferroelectric (AFE) (P) phase to exist under ambient conditions. Based on crystal chemistry viewpoint of relative change of the Goldschmidt tolerance factor (t) and polarizability, two new solid solutions were fabricated using the perovskite end member CaHfO3. It was found that the CaHfO3 effectively stabilized the antiferroelectric (AFE) P phase in NaNbO3. In this article, electrical properties and transmission electron microscopy experiments were conducted to verify the stabilization and enhancement of antiferroelectric behavior over the various solid solutions, where both structural signature of ¼{010} superlattice diffraction reflections and electrical characteristic of double polarization-electric (P-E) hysteresis were observed.

Stabilized antiferroelectricity in xBiScO3-(1-x)NaNbO3 lead-free ceramics with established double hysteresis loops

“…26 Extensive TEM characterizations in our previous studies have clearly demonstrated that both the FE Q phase and the AFE P phase coexist in pure NN in the virgin state, which was suggested by the electron diffraction pattern analysis that the AFE P phase is present as the predominant phase, together with a small portion of the FE Q phase. [10][11][12]14 The microstructures of NaNbO 3 are shown again in Figs. 2(a) and 2(b).…”

“…NaNbO 3 has an AFE P (space group Pbma) phase at ambient conditions; [5][6][7][8][9] however, the double hysteresis loops are rarely observed in NaNbO 3 due to the existence of a metastable ferroelectric (FE) Q (space group P2 1 ma) phase. [10][11][12][13][14][15][16] It is further noted that a stabilized AFE phase requires a lower tolerance factor (t). [16][17][18][19][20][21] The calculation of the Goldschmidt tolerance factor in an ABO 3type perovskite is shown in Eq.…”

“…It has been experimentally observed that the polar order can be tuned into antipolar order by decreasing the t. The lead-free BiFeO 3 is a good example; the polar R3c phase was transformed into a PbZrO 3 -like antipolar phase after adding rare earth elements to lower t. [23][24][25] It was found that the rule could also be applied to NaNbO 3 , and we predicted a broad range of different solid solution compositions that should host the AFE behavior. Recently, our group has demonstrated that AFE behavior could be obtained by adding CaHfO 3 , 10 SrZrO 3 , 11 and CaZrO 3 , 12,15 which can effectively decrease the tolerance factor and then stabilize the AFE phase in NaNbO 3 . The observed zone axis electron diffraction patterns and electric field induced signature AFE double hysteresis P-E loops verified the validity for the NaNbO 3 material system.…”

Interaction Dynamics Between Ferroelectric and Antiferroelectric Domains in a PbZrO3 -Based Ceramic

“…In AFE compounds [3,4], on the other hand, AFE → FE phase transition receives much more attention as AFE domains are nonpolar and do not directly respond to applied fields [5]. Meanwhile, in some AFE materials with certain compositions, both AFE and FE phases can coexist, either in separate grains or in single grains [5,6]. As a result, the electric fieldinduced AFE → FE phase transition occurs more readily, making these compositions suitable for devices such as electrocaloric coolers or electromechanical actuators [7,8].…”

Significantly enhanced pyroelectric performance in novel sodium niobate‐based lead‐free ceramics by compositional tuning

“…Sodium niobate (NaNbO 3 ) is one of the typical lead-free perovskite structure materials that has attracted significant interest of numerous investigators attributed to its complicated structure and phase transitions. [18][19][20] It is generally believed that NaNbO 3 presents mainly orthorhombic antiferroelectric phase (space group: Pbma) at room temperature and zero electric field. The ferroelectricity of NaNbO 3 can be stabilized by applying high electric field or forming solid solution system, such as NaNbO 3 -LiNbO 3 , NaNbO 3 -KNbO 3 , and NaNbO 3 -BaTiO 3 .…”