Disorder, metal-insulator crossover and phase diagram in high-Tc cupratesF. Rullier-Albenque1, H. Alloul2, F. Balakirev3 and C. Proust4
1 Service de Physique de l'Etat Condensé (CNRS URA 2464), CEA Saclay - 91191 Gif-sur-Yvette cedex, France
2 Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud - 91405 Orsay, France
3 National High Magnetic Field Laboratory, Los Alamos National Laboratory - Los Alamos, NM 87545, USA
4 Laboratoire National des Champs Magnétiques Pulsés, UMR CNRS-UPS-INSA 5147 - Toulouse, France
received 19 October 2007; accepted in final form 4 December 2007; published February 2008
published online 4 January 2008
We have studied the influence of disorder induced by electron irradiation on the normal-state resistivities of optimally and underdoped YBa2Cu3Ox single crystals, using pulsed magnetic fields up to 60 T to completely restore the normal state. We evidence that point defect disorder induces low-T upturns of which saturate in some cases at low T in large applied fields as would be expected for a Kondo-like magnetic response. Moreover, the magnitude of the upturns is related to the residual resistivity, that is to the concentration of defects and/or their nanoscale morphology. These upturns are found quantitatively identical to those reported in lower-Tc cuprates, which establishes the importance of disorder in these supposedly pure compounds. We therefore propose a realistic phase diagram of the cuprates, including disorder, in which the superconducting state might reach the antiferromagnetic phase in the clean limit.
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).
74.62.Dh - Effects of crystal defects, doping and substitution.
74.72.Bk - Y-based cuprates.
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