Study Of Electrical, Chemical And Structural Characteristics Of Superconductor Thin Film Obtained By Polymeric Precursor
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Study Of Electrical, Chemical And Structural Characteristics Of Superconductor Thin Film Obtained By Polymeric Precursors Method C.L. Carvalho, R.O. Peruzzi, D.R. Junior1 Departamento de Física e Química - UNESP - Ilha Solteira /SP Caixa Postal 31 Brazil 1 Departamento de Engenharia de Materiais – FAENQUIL – Lorena / SP ABSTRACT Superconductor films of the BSCCO system have been grown by dip coating technique with good success. The chemical method allows us to grow high temperature superconductor thin films to get better control of stoichiometry, large areas and is cheaper than other methods. There is a great technological interest in growth oriented superconductor films due anisotropic characteristics of superconductor materials of high critical temperature, specifically the cuprates, as we know that the orientation may increase the electrical transport properties. Based on this, the polymeric precursor method has been used to obtain thin films of the BSCCO system. In this work we have applied that method together with the deposition technique known as dip coating to obtain Bi-based superconductor thin films, specifically, Bi1.6Pb0.4Sr2.0Ca2.0Cu3.0Ox+δ , also known as 2223 phase with a critical temperature around 110 K. The films with multilayers have been grown on crystalline substrates of LaAlO3 and orientated (100) after being heat treated around 790oC - 820oC in lapse time of 1 hour in a controlled atmosphere. XRD measurements have shown the presence of a crystalline phase 2212 with a critical temperature around 85 K with (001) orientation, as well as a small fraction of 2223 phase. SEM has shown a low uniformity and some cracks that maybe related to the applied heat treatment. WDS has also been used to study the films composition. Different heat treatments have been used with the aim to increase the percentage of 2223 phase. Measurements of resistivity confirmed the presence of at least two crystalline phases, 2212 and 2223, with Tc around 85 K and 110 K, respectively. INTRODUCTION Recently, it has been noted that the research on superconductor materials has continued to be an area of great technological advance, although the critical temperature of transition conductors/superconductors has not increased and in some cases researchers returned to study metal alloys (MgB2). In such cases, the interest in obtaining devices for electronic circuits to improve the technology has received a great emphasis, mainly in electronic circuits [1]. However, there are some problems to obtaining homogeneous films, large areas, 100% pure phase, etc. One of the most approached problems is the expected superconductor phase with high degree of purity and epitaxial growth because it will be applied to some concepts in the electronic components used in semiconductors and superconductors [1]. Thus, instead of using expensive physical processes, we have observed attempts to use chemical processes together, such as dip - spin-coating deposition, that are simple and cheap and have shown high efficiency in some cases [2]. Theref
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