Physical Review Letters

Universal correlations between Tc and nsm* (Carrier density over effective mass) in High-Tc cuprate cuperconductors

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The muon-spin-relaxation rate has been measured in sixteen specimens of high-Tc cuprate superconductors (the 2:1:4, 1:2:3, 2:2:1:2, and 2:2:2:3 series). This has allowed us to study the magnetic field penetration depth and thus the superconducting carrier density ns divided by the effective mass m*nsm*). A universal linear relation between Tc and (T0)nsm* has been found with increasing carrier doping. In heavily doped samples, however, Tc shows saturation and suppression with increasing nsm*. This saturation starts at different values of nsm* for materials with different multiplicities of CuO planes. © 1989 The American Physical Society.