Physical properties and crystal microstructure of the single crystal fibres made from rare-earth oxides

摘要

Single crystal fibres on a basis rare-earth oxides are promising materials for technical application, in particular for radiation delivery in a near and mid-IR range. In the fibres shape Eu³⁺:Y2O3 [1], Ln³⁺:Gd2O3 (Ln=Nd, Eu, Er) [2,3] single crystals have been received earlier and their luminescent properties have been studied. The goal of our study consisted in the interrelation analysis between a microstructure of fibres and their such property as the plasticity expressed in their ability to be easily bent. Another goal was the study of nonlinear properties consisted in the possibility to produce super continuum generation during the transmission of the ultrashort light pulses. Fibres Ln2O3 (Ln=Sm, Eu, Gd) have been grown up by a method of “a laser minipedestal” on ZrO2 crystal seed. Among the grown up fibres there were both fragile, and flexible plastic. According to X-ray crystal phase analysis in all of them Ln2O3 are crystallized in monoclinic system and do not contain additional cubic crystal phase stable at low temperatures (a limit of detection of about 1 %). A series X-ray diffraction patterns obtained with initial, bent and straightened fibres shows, that at deformation the reflexes on Laue pattern are diffused, but there is practically full restoration of clearness of reflexes at restoration of the initial shape of a fibre. The morphology of the samples surface was studied, the chemical composition is determined by the X-ray microanalysis, orientation of crystals is established by a method of diffraction of back scattered electrons (EBSD). On the fibres surface the rings are observed and they are allocated with distances between them of about 0,3–2 µm (Fig. 1)