Local structure analysis of (Na,K,Li)NbO

Yoneda, Yasuhiro   ; Takada, Eri*; Nagai, Haruka*; Kikuchi, Takeyuki*; Kobune, Masafumi*

(Na,K)NbO has been a candidate for lead-free piezo electric material, since it shows a novel piezoelectric properties by making a mixture between (Na,K)NbO and LiNbO. (Na,K,Li)NbO lies around a morphotropic phase boundary at room temperature, and it has been reported some co-existing phases of a tetragonal and a orthorhombic structures. We re-examined the crystal structure of (Na,K,Li)NbO by using high-energy synchrotron X-ray. It was found that (Na,K,Li)NbO has a monoclinic structure at room temperature. Moreover, we found a phase transition at approximately 200 K, in which the intensity of Bragg peaks changed drastically. The novel piezoelectric response of (Na,K,Li)NbO is caused by modifying the phase transition below room temperature.