Superconductor edited by Adir Moysés Luiz SC I YO Superconductor Edited by Adir Moysés Luiz Published by Sciyo Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2010 Sciyo All chapters are Open Access articles distributed under the Creative Commons Non Commercial Share Alike Attribution 3.0 license, which permits to copy, distribute, transmit, and adapt the work in any medium, so long as the original work is properly cited. After this work has been published by Sciyo, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published articles. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Iva Lipovic Technical Editor Teodora Smiljanic Cover Designer Martina Sirotic Image Copyright Creasence, 2010. Used under license from Shutterstock.com First published October 2010 Printed in India A free online edition of this book is available at www.sciyo.com Additional hard copies can be obtained from publication@sciyo.com Superconductor, Edited by Adir Moysés Luiz p. cm. ISBN 978-953-307-107-7 SC I YO.C O M WHERE KNOWLEDGE IS FREE free online editions of Sciyo Books, Journals and Videos can be found at www.sciyo.com [...]... +V +III, +V +II, +IV +II, +III, +IV +I, +III +IV, +V, +VI [Xe]4f145d106s26p3 [Ar]3d104s1 [Ar]3d64s2 [Kr]4d35s2 [Xe]4f145d106s26p2 [Ar]3d24s2 [Xe]4f145d106s26p1 [Xe]4f145d46s2 Table 2 Electron configurations and oxidation states of some metals Note also that in the superconductor (7) (without copper), Bi may have the oxidation states Bi(+III) and Bi(+V) In the superconductor (11 ), an example of the. .. of a metallic superconductor However, the isotopic effect is not clearly observed in oxide superconductors Superconductor (1) NbO (2) KxWO3 (3) LiTi2 + xO4 (4) BaPb1 - xBi xO3 (5) La2 - xBaxCuO4 (6) YBa2Cu3O7 - x (7) Ba1 - xKxBiO3 (8) BiSrCaCu2O6 + x (9) Tl2Ba2Ca2Cu3O9 + x (10 ) HgBa2Ca2Cu3O8 + x (11 ) NdFeAsO1-x Year 19 33 19 67 19 73 19 75 19 86 19 87 19 88 19 88 19 88 19 93 2008 TC 1. 5 6.0 1. 2 13 30 90 30 10 5... between two superconductors For metallic superconductors the width of the insulator film should be of the order of 10 4 angstroms However, for high-Tc oxide superconductors, where the coherence length is of the order of the distance between two atoms, the order of magnitude of the width of the insulator film should be about one angstrom, and the production of this film should be a very difficult task Therefore,... in the 4 Superconductor superconductor (4) Pb may have the oxidation states: Pb( +II) and Pb(+IV) and Bi may have the oxidation states Bi(+III) and Bi(+V); in the copper oxide superconductors (5), (6), (8), (9) and (10 ) Cu may have the oxidation states Cu(+I) and Cu(+III) Metal Electron configurations Oxidation states As Bi Cu Fe Nb Pb Ti Tl W [Ar]3d104s24p3 +III, +V +III, +V +I, +II, +III +II, +III,... concentrations of these ions should be (1/ 3)Cu(+I), (1/ 3)Cu( +II) and (1/ 3)Cu(+III) However, we may suppose that by oxidation reactions, (1/ 3)Cu( +II) ions may be completely converted to (1/ 3)Cu(+III) ions In this case, the maximum concentration of the Cu(+III) ions should be: (1/ 3) + (1/ 3) = (2/3) Thus, the optimal doping should correspond to the following maximum relative concentrations: (1/ 3)Cu(+I) ions... in the references (Cava, 2000) The history of oxide superconductors begins in 19 33 with the synthesis of the superconductor NbO; with Tc = 1. 5 K (Sleight, 19 95) In 19 75 it was discovered the oxide superconductor BaPb0.7Bi0.3O3 (Sleight et al., 19 75) with Tc = 13 K In 19 86, the oxide superconductor Ba0 .15 La1.85CuO4 with Tc = 30 K has been discovered (Bednorz & Müller, 19 86) The expression “high-Tc superconductors ... occupied by the system It is generally accepted that BEC occurs when the interparticle separation is of the order of the delocalization λdB (Silvera, 19 97) The thermal de Broglie wavelength λdB is a measure of the thermodynamic uncertainty in the localization of a particle of mass M with the average thermal momentum Thus, λdB is given by λdB = h/[3MkT ]1/ 2 (1) where k is Boltzmann’s constant Equation (1) shows... (b) the order of magnitude of the coherence length (the mean distance between two electron pairs) is in accordance with the order of magnitude of the distance between the electron clouds of two neighboring ions (see Section 2); (c) the nonmonotonic dependence of Tc on the carrier concentration is explained by the hypothesis of double charge fluctuations and optimal doping (Sections 3 and 11 ) The theory... order of 10 -4 cm In high-Tc superconductors, the coherence length is anisotropic and of the order of angstroms For example, in the system Bi-Sr-Ca-Cu-O, the coherence length is approximately equal to 1 angstrom (10 -10 cm) along the c-axis and approximately equal to 40 angstroms in the transverse direction (Davydov, 19 90) c In high-Tc superconductors, the dependence of Tc on the concentration of charge... 38, 15 , pp 10 900 -10 902 Foltin, J (19 89) Difference in high temperature superconductivity of two families of cuprate oxides Physics Letters A; 14 1, 8-9, pp 427-428 Ganguly, P & Hegde, M S (19 88) Evidence for double valence fluctuation in metallic oxides of lead Phys Rev B; 37, 10 , pp 510 7- 511 1 Hiroi, Z.; Takano M.; Azuma, M & Takeda, Y (19 93) A new family of copper oxide superconductors Srn+1CunO2n +1+ δ . [Ar]3d 10 4s 2 4p 3 +III, +V Bi [Xe]4f 14 5d 10 6s 2 6p 3 +III, +V Cu [Ar]3d 10 4s 1 +I, +II, +III Fe [Ar]3d 6 4s 2 +II, +III, +IV, +V Nb [Kr]4d 3 5s 2 +III, +V Pb [Xe]4f 14 5d 10 6s 2 6p 2 . Tl 2 Ba 2 Ca 2 Cu 3 O 9 + x 19 88 11 0 Shimakawa et al., 19 88 (10 ) HgBa 2 Ca 2 Cu 3 O 8 + x 19 93 13 0 Schilling & Cantoni, 19 93 (11 ) NdFeAsO 1- x 2008 54 Yang et al., 2008 Table 1. Superconductors containing. oxide superconductors is found in the references (Cava, 2000). The history of oxide superconductors begins in 19 33 with the synthesis of the superconductor NbO; with T c = 1. 5 K (Sleight, 19 95).