Potential Advantage of Multiple Alkali Metal Doped KNbO3 Single Crystals

Hideo Kimura,Tingting Jia,Lei Guo,Qiwen Yao,Rumi Tanahashi,Hongyang Zhao,Zhenxiang Cheng

doi:10.3390/cryst4030190

Abstract

Potassium niobate crystal KNbO3 (KN) is a well-known crystal for lead free piezoelectric or nonlinear optical applications. The KN crystal has been studied in both single crystal form and in thin film form which has resulted in many review articles being published. In order to exceed the KN crystal, it is important to study KN phase forming and doping effects on the K site. This article summarizes the authors’ study towards a multiple alkali metal doped KN crystal and related single crystals briefly from the viewpoint of crystal growth.

Highlights

The potassium niobate crystal KNbO3 (KN) is well known to be a nonlinear optical crystal that shows wavelength modulation [1,2,3,4,5]
We summarize our past perverse study toward a multiple alkali metal dope KN crystal from a crystal grower’s viewpoint
Crystal growth from high temperature solutions using the halogen lamp-heated floating zone (Fz)-PD technique can be employed for forming fiber crystals

Summary

Introduction

The potassium niobate crystal KNbO3 (KN) is well known to be a nonlinear optical crystal that shows wavelength modulation [1,2,3,4,5]. The KN crystal can be grown with high quality and low lattice defects, especially in fiber shape [11]. It is difficult, to grow large size and high quality crystals since the melting mode of the KN crystal is incongruent [7]. KN crystal should in any case be grown from high temperature solutions; it is important to know its phase diagram. A few reports on the phase diagram of the KN based crystals that are believed to be line compounds were found [12]. Many review articles on the KN crystal have been published up to the present from the viewpoint of piezoelectric applications, such as crystal growth and piezoelectric SAW properties for acoustic filter and so on. We summarize our past perverse study toward a multiple alkali metal dope KN crystal from a crystal grower’s viewpoint

Formation of KNbO3 Crystal from Stoichiometric Melts

The KNbO3 Single Crystal in Fiber Shape

The Past Pb2KNb5O15 Crystal

The Effects of K4Nb6O17 on KNbO3

Summary