Effects of A-Site Ions on the Phase Transition Temperatures and Dielectric Properties of (1-x)(Na_0.5K_0.5)NbO₃–xAZrO₃ Solid Solutions

Abstract

(1-x)(Na0.5K0.5)NbO3–xAZrO3 (A = Sr, Ca) solid solutions have been prepared to study the effcts of A-site ions on the successive phase transition temperatures. It is found that the phase diagram for the solid solutions are very similar: with increasing x, the cubic–tetragonal phase transition temperature T C–T and the tetragonal–orthorhombic phase transition temperature T T–O shift to the lower-temperature region, while the orthorombic–rhombohedral phase transition temperature T O–R shifts to the higher temperature region. When x is between 8 and ∼15 molar percentage, the orthorhombic–rhombohedral phase transition temperature is higher than room temperature and the (1-x)(Na0.5K0.5)NbO3–xAZrO3 solid solutions exhibit rhombohedral symmetry at room temperature. It is found that T C–T is affected by A-site ions; while T T–O and T O–R are almost independent of A-site ions.

Effects of strontium doping on microstructure and functional properties of solution-derived potassium sodium niobate thin films

“…All of these can be used to explain the enhancement of ferroelectricity in the KNN F -0.5Sr and KNN F -1Sr films. Similar was observed in the (1x)(Na 0.5 K 0.5 )NbO 3 -xAZrO 3 (A = Ca 2+ , Sr 2+ ) solid solutions [19].…”

Simultaneously achieved high‐energy storage density and efficiency in (K,Na)NbO3‐based lead‐free ferroelectric films

“…With the content of Mn increasing from 0 to 2 mol%, distorted single {200} peaks were observed, implying a pseudo cubic structure of these films (x = 0, 0.5, & 2). Moreover, according to the phase diagram of (1x)(Na 0.5 K 0.5 )NbO 3 -xAZrO 3 (A = Ba, Sr, Ca; 0 ≤ x ≤ 0.25) solid solutions as proposed by Wang et al, 29 when CaZrO 3 content is less than 5 mol%, the films exhibit orthorhombic structure. Therefore, the main phase of KNN-LT-CZ5 films with Mn content below 2 mol% should be orthorhombic phase with a ≈ b ≈ c, which can be described by a pseudo cubic structure very well.…”

Morphotropic Phase Boundary Slope of (K,Na,Li)NbO3–BaZrO3Binary System Adjusted Using Third Component (Bi,Na)TiO3Additive

“…[11][12][13][14][15][16][17][18][19][20][21][22] Usually, there are three effective ways to improve the properties of lead-free piezoceramics: nanodomain engineering, domainorientation engineering, and MPB engineering. The former two ways are based on fabrication processes, and good approaches and results have been reported.…”