Domain evolution with electric field and delineation of extrinsic contributions in (K, Na, Li)(Nb, Ta, Sb)O3 single crystal

Abstract

Extrinsic contributions play an important role in the functionalities of ferroelectric materials, while domain structure evolution is crucial for understanding the extrinsic dielectric and piezoelectric responses. In this work, domain configuration changes with an electric field applied along [001] C in the tetragonal (K, Na, Li)(Nb, Sb, Ta)O 3 single crystal were studied by means of polarizing light microscopy. Results show that parts of the spontaneous polarizations in the (001) C plane are switched to [001] C direction, while others still stay in the (001) C plane due to high induced internal stresses. Single domain state cannot be achieved even under a high electric field. After being poled along [001] C , the volume fraction of domains with polarzations in the (001) C plane is still about 25.2%. The extrinsic contributions to the dielectric constant are 15.7% and 27.2% under the E field of 1 kV/cm and under 2 kV/cm, respectively, estimated by the Rayleigh analysis. (K, Na)NbO 3 (KNN) based piezoelectric materials have been extensively studied in the last decade as lead-free alternatives to PZT ceramics due to their high Curie temperature (T C > 300 C) and high piezoelectricity (d 33 > 300 pC/N). [1][2][3][4] Great improvement in electrical performance has been made in recent years, focusing on the modification of compositions and optimization of preparation techniques. 5,6 In general, the dielectric and piezoelectric properties can be divided into two parts: intrinsic and extrinsic contributions. The intrinsic response is related to the relative ionic shift that preserves the crystal structure orientation and crystal lattice symmetry, while the extrinsic response is ascribed to the domain wall motions. 7,8 The extrinsic contribution plays a critical role in various functionalities, such as dielectric properties, piezoelectric activity, and energy loss behavior. 9,10 In addition, understanding the mechanism of domain wall motions is very helpful to get some insight into the nonlinearity, frequency dispersion, and aging of physical properties. 11 For the investigation of domain structures, single crystals are preferred over ceramics because dynamic process of domain evolution with E filed and temperature can be easily observed in single crystals. Up to date, studies on the domain evolution in KNN based materials are still limited due to the lack of available good quality single crystals, especially extrinsic contributions to dielectric and piezoelectric properties have not been quantified. In order to gain further insight into the high electromechanical properties of KNN-based materials, it is necessary to study domain evolution and to determine the level of extrinsic contributions. In our previous work, large-sized high quality KNN-based single crystals with different compositions have been grown by the topseeded solution growth (TSSG) method, which allowed us to carry out further research on domain configurations and extrinsic responses. [12][13][14][15][16] Above room temperature, KNN materials are either ...

Temperature‐ and E‐field‐dependent domain configuration and electrical properties in (K, Na, Li)(Nb, Ta, Sb)O3 single crystal

“…There are six spontaneous polarizations ( P S ) along <001> C family exist in the tetragonal phase (denoted by P S 1, 2, … 6), as shown in Figure A. Both 90° and 180° domains are permissible . Under an E field along [011] C , all P S vectors switch to directions close to E field, for example, [001] C and [010] C ( P S 1 and 4), as shown in Figure B.…”

“…Both 90°and 180°d omains are permissible. [28][29][30][31] Under an E field along [011] C , all P S vectors switch to directions close to E field, for example, [001] C and [010] C (P S 1 and 4), as shown in Figure 2B. "2T" engineered domain structure is formed, in which only 90°domain is permissible.…”

Temperature dependence of intrinsic and extrinsic dielectric contributions in 0.27Pb(In1/2Nb1/2)O3–0.46Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 single crystals

“…Hence, generally speaking, the extrinsic part contributes to the irreversible response while the intrinsic part contributes to the reversible one. Therefore, the Rayleigh law can be used to separate the intrinsic and extrinsic contributions in ferroelectric crystals . The dielectric Rayleigh relationship can be expressed as follows: where ϵ in is the intrinsic dielectric permittivity and E 0 is the amplitude of the measured ac E field.…”

(K,Na)NbO3-based piezoelectric single crystals: Growth methods, properties, and applications

“…Highest properties were obtained after poling with 6 kV/mm, while higher fields resulted in overpoling. The same group has previously also attempted to obtain monodomain state in [001] Coriented tetragonal (K,Na,Li)(Nb,Sb,Ta)O 3 crystals [141], i.e., the "1T" configuration shown in Fig. 8(b).…”