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

Abstract

E‐field‐ and temperature‐dependent domain evolution of lead‐free tetragonal (K, Na, Li)(Nb, Sb, Ta)O3 (KNLNTS) single crystals as well as its corresponding electrical properties have been investigated. When E field is applied along [011]C direction, (2T) engineered domain structure is formed. Spontaneous polarizations switch under a critical electric field (around 4‐5 kV/cm), resulting in significant changes in domain structure and great improvement in piezoelectric properties. Furthermore, it is found that piezoelectric constant d31 and electromechanical coupling factor k31 of [011]C poled KNLNTS single crystal decrease with temperature. The extrinsic and intrinsic piezoelectric responses are discussed from the viewpoint of domain structure and lattice distortion, respectively. Our results show that the nanodomain structure relaxes and the lattice distortion declines with temperature, resulting in reduction of extrinsic and intrinsic piezoelectric responses, respectively. Therefore, the piezoelectric instability is ascribed to the decrease of both extrinsic and intrinsic contributions. This work provides a better understanding of domain engineering technique, and the useful information on the improvement of both piezoelectricity and temperature stability of the lead‐free piezoelectric materials.

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

“…The ferroelectric domain structures in KNN-based single crystals were investigated by several authors using polarized light microscopy (PLM) [48,51,73,132,133,134,135], transmission electron microscopy (TEM) [50,74], and piezoresponse force microscopy (PFM) [101,136,137,138]. Unlike the complicated zigzag or herringbone-like structures reported for KNN polycrystalline ceramics [139], the domains in single crystals arrange into less-complex configurations and are generally larger in size.…”

“…This was accompanied by an increase of the piezoelectric coefficient from 270 pC/N to 350 pC/N and relative permittivity from 730 to 850. Influence of poling on the [011] C -oriented tetragonal (K,Na,Li)(Nb,Sb,Ta)O 3 crystal was studied by Wang et al [135]. Applying 4-5 kV/cm along the [011] C direction switched the polarization vectors into the nearby h100i C directions and the "2T" engineered domain structure [ Fig.…”