KTa_(1-x)Nb_xO_3晶体生长固/液边界层结构的微区研究

Micro-structure of growth solid-liquid boundary layer of KTa_(1-x)Nb_xO_3 crystal

测量了KTa1-xNbxO3(KTN)晶体在常温和高温下的Raman光谱;实时测量了晶体生长过程中,固/液边界层内以及边界层两侧的晶体和熔体的高温显微Raman光谱.通过光谱分析获得了KTN晶体生长固/液边界层内的结构特征,以及晶体生长基元从熔体结构经边界层过渡到晶体结构的变化规律.研究表明,KTN熔体中的[Ta/NbO3]结构基团进入到生长边界层后逐步转化为[Ta/NbO6]八面体结构基团,已具有KTN单胞的一些特征.进而讨论了以[Ta/NbO6]八面体为生长基元的KTN晶体有(100),(100),(010)和(010)晶面容易显露的生长习性,发现KTN晶体生长固/液边界层厚度约为80—90μm.

Raman spectra of KTa1-x NbxO3（KTN） single crystal,its melt,and the solid-liquid boundary layer in the growing process at different temperatures were measured in-situ.The structure transformation in KTN crystal growth process was investigated.The results showed that the [Ta/NbO3]entities came into solid-liquid boundary layer from KTN melt,and they were transformed to [Ta/NbO6]octahedron entities.And the structure of [Ta/NbO6]octahedron entity was just like that of KTN single cell.Regarding [Ta/NbO6]octahedron as growth units,the growth habit of KTN crystal in which the（100）,（100）,（010） and（010） faces are easily revealed was discussed.The thickness of the growth solid-liquid boundary layer of KTN crystal was about 80—90 μm.