Fabrication Of GdBa₂Cu₃O_7-x Films By Fluorine-free Sol-gel Process

GdBa2Cu3O7-x(GdBCO)high temperature superconducting thin films have high critical transition temperature and current carrying capacity under strong magnetic field,which have potential applications in superconducting power systems and superconducting microelectronic devices.At present,the GdBCO superconducting film prepared by Sol-Gel method mainly adopts the full fluorine or low-fluorine method.During the heat treatment process,corrosive HF gas will be generated,which leads to a long period of heat treatment,poor surface quality and environmental pollution.Therefore,it is of great significance to explore the preparation of GdBCO superconducting thin films by the fluorine free Sol-Gel method.In this paper,the following research work has been done around the preparation of GdBCO thin films by Sol-Gel method.(1)The preparation of fluorine-free GdBCO sol was studied,using gadolinium acetate,barium acetate and copper acetate as starting materials and methanol as solvent and chose appropriate additives.The formation of fluorine free GdBCO sol and the phase formation mechanism of GdBCO thin films were studied.The results showed that the organometallic substances in GdBCO gel films were decomposed into corresponding oxides and carbonates at low temperature,and then the GdBCO phases were formed by reaction of oxides and carbonates at high temperature.(2)The process of preparing GdBCO superconducting thin films by fluorine free Sol-Gel method was discussed.The GdBCO gel film was prepared on LaAlO3(LAO)single crystal substrate.The gel film was heated to 820℃ degree heat preservation 90min,and the oxygen partial pressure was 1169Pa for high temperature heat treatment.The GdBCO superconducting thin films with biaxial texture were successfully prepared.The superconducting transition temperature was 90K and the critical current density reached 1.23MA/cm2.(3)Transparent and stable Gd/BzAc sol was prepared by using gadolinium acetate as raw material,methanol as solvent and henzoyl acctone(BzAcH)as chemical modifier.The chemical reaction path of Gd/BzAc sol was discussed;UV photorcccptor characteristics of Gd/BzAc gel film were further studied;and the micro patterning of Gd/BzAc gel film was prepared by ultraviolet photoreceptor of gel film,and Gd2O3 thin film fine graphics were prepared.It lays a foundation for the preparation of high temperature superconducting GdBCO thin films and their tine patterns.