Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Fabrication of Lu Doped Ybco Thin Films by Pulsed Laser Deposition Technique and Their Characterization(Izmir Institute of Technology, 2010) Sezer, Bahtiyar Şirvan; Abukay, Doğan; Abukay, Doğan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyNearly twenty years ago YBCO was the first superconductor discovered with a transition temperature above the boiling point of liquid nitrogen, the .fascinating. limit for high temperature superconductivity. From the day forward, the interest in this ceramic compound has not diminished. YBCO is one of the most promising materials for the application of high temperature superconductors (HTS) because it is able to carry a technically useful current density in applied fields at 77 K. A lot of experiments guided to investigate the basic properties of the HTS and to further the theoretica understanding of them also used YBCO, because this progress has been achieved in the preparation of bulk samples, and especially thin films deposited by a various methods. The aim of the experimental investigation presented in this thesis was to produce high quality epitaxial Lutetium doped YBCO thin films on MgO substrates prepared by pulsed laser deposition. For this purpose, bulk Lu2O3 powder was mixed into YBCO by using solid-state reaction method and pressed to make a stoichiometric target for PLD process. KrF excimer laser was worked at 14 Kv with repetition rates ranging from 3 to 5 Hz to deposited Y0.9Lu0.1Ba2Cu3O7-. thin films at a substrate temperature of 800 oC. The surface of the films were characterized by employing XRD, SEM, EDX and AFM techniques.Master Thesis High Temperature Superconducting Yba2cu3o7-X Transitation Edge Bolometers (tebs) for Infrared Region(Izmir Institute of Technology, 2008) Günel, Hacı Yusuf; Abukay, Doğan; Abukay, Doğan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThe thesis focuses on electrical and bolometric characterization of high temperature superconducting YBCO transition edge bolometers. In this study, superconducting YBCO thin films grown on MgO, LaAlO3 and SrTiO3 substrates were first characterized structurally via x-ray diffraction and scanning electron microscopy.They then were patterned into bolometers and their electrical and bolometric characterizations were carried out. The results of these characterizations were fitted to the RC model. In addition, figures of merit for these devices, such as noise equivalent power (NEP) and detectivity, were measured and calculated.During this work, the patterning process was carried out by standard photolithographic processes and chemical etching. We have also investigated the effect of dimensions of our devices on the performance of bolometers. The electrical and bolometric characterizations comprised of resistance versus temperature (R-T), amplitude of response versus temperature, amplitude of response versus chopping frequency (A-F) and noise voltage measurements. Finally, the performance of our devices were compared to literature and found to be similar to or better than those of similar devices in literature.