Ferroelectric properties in KNbO3 thin films probed by optical second harmonic generation

Abstract

Articles you may be interested inStructural and dielectric properties of laser ablated BaTiO3 films deposited over electrophoretically dispersed CoFe2O4 grains A comprehensive investigation on the phase transformation behavior and electrical properties of ( Pb 1 − x Ba x ) ZrO 3 ( 0 ≤ x ≤ 0.5 ) thin films Ferroelectric phase transitions and the structure of KNbO 3 nanometer-thick films deposited by Metal-organic chemical-vapor deposition technique on a MgO͑100͒ substrate are studied. Thin KNbO 3 films of the average thickness from 20 to 150 nm possess a grainlike structure with a lateral grain size of about 250 nm. Such films reveal ferroelectric properties similar to KNbO 3 single crystal. Temperature dependencies of optical second harmonic generation intensity show that the Curie temperature T C of the nanometer-thick KNbO 3 films is about 30°C lower than the T C of KNbO 3 single crystal, which is attributed to size effects in KNbO 3 nanograins.

Size Effect on Crystal Structure and Phase Transition of Potassium Niobate

“…7. On the other hand, Murzina et al made a KNbO 3 thin film composed of 150-300 nm nanograins and reported that the tetragonal-cubic phase transition temperature of the film is about 25 K lower than the bulk [26]. We consider that our results do not contradict with those of the thin film.…”

Size dependence of the polarization and dielectric properties of KNbO3 nanoparticles

“…[12][13][14] Similar to BaTiO 3 , KNbO 3 undergoes the same sequence of phase transitions, from a rhombohedral to an orthorhombic, a tetragonal and nally to a cubic as the temperature increases. However, the transition temperatures of KNbO 3 (263 K, 498 K and 708 K on heating) are considerably higher than those of BaTiO 3 (183 K, 278 K and 393 K).…”

Thermal evolution of the crystal structure and phase transitions of KNbO 3

“…In recent years the phase transitions of KNbO 3 have been investigated by several different techniques including infrared spectroscopy [7–9], Raman spectroscopy [8–11], thermal expansion measurements [11,12], second harmonic generation [13] and luminescence measurements [14]. However, a complete set of unit cell parameters and insight into the crystal structure across the phase transitions have so far not been reported.…”

“…Following the discovery of lead zirconate titanate in 1954 [4], the interest for KNbO 3 dropped, but was reignited in the early 2000s due to legislation introduced to reduce the use of lead in technological applications [5,6]. In recent years the phase transitions of KNbO 3 have been investigated by several different techniques including infrared spectroscopy [7][8][9], Raman spectroscopy [8][9][10][11], thermal expansion measurements [11,12], second harmonic generation [13] and luminescence measurements [14]. However, a complete set of unit cell parameters and insight into the crystal structure across the phase transitions have so far not been reported.…”