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Abstract
Planar oxygen nuclear magnetic resonance (NMR) relaxation and shift data from all cuprate superconductors available in the literature are analyzed. They reveal a temperature-independent pseudogap at the Fermi surface, which increases with decreasing doping in family-specific ways, i.e., for some materials, the pseudogap is substantial at optimal doping while for others it is nearly closed at optimal doping. The states above the pseudogap, or in its absence are similar for all cuprates and doping levels, and Fermi liquid-like. If the pseudogap is assumed exponential it can be as large as about 1500 K for the most underdoped systems, relating it to the exchange coupling. The pseudogap can vary substantially throughout a material, being the cause of cuprate inhomogeneity in terms of charge and spin, so consequences for the NMR analyses are discussed. This pseudogap appears to be in agreement with the specific heat data measured for the YBaCuO family of materials, long ago. Nuclear relaxation and shift show deviations from this scenario near Tc, possibly due to other in-gap states.
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Magishi K, Kitaoka Y, Zheng G, Asayama K, Kondo T, Shimakawa Y, Manako T, Kubo Y. Magnetic excitation and superconductivity in overdoped TlSr2CaCu2O7- delta : A 63Cu NMR study. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:10131-10142. [PMID: 9984753 DOI: 10.1103/physrevb.54.10131] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Magishi K, Kitaoka Y, Zheng G, Asayama K, Tokiwa K, Iyo A, Ihara H. 63Cu NMR probe of superconducting properties in HgBa2Ca2Cu3O8+ delta : A possible reason for Tc=133 K. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:R8906-R8909. [PMID: 9982482 DOI: 10.1103/physrevb.53.r8906] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Mayaffre H, Wzietek P, Jérome D, Lenoir C, Batail P. Superconducting state of kappa -(ET)2CUBr studied by 13C NMR: Evidence for vortex-core-induced nuclear relaxation and unconventional pairing. PHYSICAL REVIEW LETTERS 1995; 75:4122-4125. [PMID: 10059820 DOI: 10.1103/physrevlett.75.4122] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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