Fabrication And Studies On Ab-plane Texture Characteristics Of Bi-2212Thin Films

Bi-superconducting thin film materials has lots of characteristics such as large surface area, high defect density, often in a metastable state organizations, performance is sensitive to the crystal parameters and factors affecting crystal orientation are complex, together with the high-quality thin film growth need high technology and equipment,so how to choose the appropriate method and the process parameters in thin films to induce a reasonable texture distribution, then in the crystallization process to manipulate the texture of crystal orientation and learning the impact on the performance of films is still difficult. Therefore, the correct analysis of Bi-superconducting film texture characteristics has been an important prerequisite for the control of crystal orientation.The EBSD technology enables organizations to observe the morphology of crystal orientation and at the same time allow the microstructure associated with the crystallographic information and accurate measurement of materials texture quickly. Now in metallurgy, materials processing, it has been widely used. However, the application and research of Bi-2212superconducting films has not yet been carried out. This paper used the EBSD technique, focusing on the ab-plane texture characteristics of Bi-2212superconducting films and have a related research. The detail contents of the dissertation are as follows:1. Firstly, make Bi-2212superconducting thin films by the method of MBE on MgO and STO which were two kinds of substrates. The influences of composition, substrate temperature and the ozone partial pressure on the formation of Bi-2212phase in the film were investigated in detail.2. Use the EBSD technique tested these two kinds of films,and by SEM EBSD generated photo, image quality map, phase distribution analysis we appreciate that the Bi-2212films which on the epitaxial growth of MgO (100) single crystal substrates, as substrate materials and superconducting thin films a high mismatch, the film growth process in the strain still exists in the sample. When used a lower mismatch STO substrate as the substrates, basically eliminated strain and had a high Kikuchi pattern recognition rate. At the same time through the sample pole figures, inverse pole figure we analysis of the sample c axis and ab axis orientation. Shows the films were growing epitaxial along the c-axis. This is because the film growth mode. However, in the ab axis, the texture of sample growth on the STO is more distinct than it was on MgO substrate.