铁电单晶三维定向的X射线衍射方法

Three-Dimensional Orientation of Ferroelectric Single Crystals Using X-Ray Diffraction Method

目前采用坩埚下降法生长的弛豫铁电单晶为圆柱状晶体,无自然结晶面,晶体在切割加工前必须进行三维定向。本文提出了一种利用粉末X射线衍射仪和X射线定向仪确定铁电单晶三维方向的简便方法。通过粉末X射线衍射仪确定任意切割晶面的最强衍射峰,然后利用X射线定向仪确定最强衍射峰准确的切割面,再通过X射线定向仪确定两个晶面的交线方向,从而获取晶体的三维方向,进而指导晶体切割加工。使用该方法对Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)铁电单晶进行三维定向,结果证明该定向方法具有准确度高、效率高、操作方便、晶体损耗少的特点。该方法也适用于其他晶体材料的定向。

The relaxor-based ferroelectric single crystals grown by vertical Bridgman method are cylindrical ingots with no natural crystallization face.The crystallographic orientations are required before cutting and processing.In this work,we proposed a simple method for determining crystallographic orientations of ferroelectric single crystal using powder X-ray diffractometer and X-ray orientation instrument.Firstly,the Miller indices of the strongest diffraction peak of arbitrarily cut plane are determined by a powder X-ray diffractometer.Secondly,the cut plane of crystal ingots is determined according to the Miller indices of the strongest diffraction peak by an X-ray orientation instrument.Thirdly,the intersection direction of the two crystallographic planes is obtained by X-ray orientation instrument.The three-dimensional orientations of ferroelectric single crystal are obtained based on the intersection direction and the crystallographic planes of the strongest diffraction peak.The application of this method to Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)single crystals demonstrates that it is a high accurate,high efficient,convenient,and waste-free method for crystallographic orientation.In addition,this method is also suitable for other crystals.