Antiferromagnetism, superconductivity, and pseudogap in three-layered high-Tc cuprates Ba2Ca2Cu3O6(F,O)2 probed by Cu-NMR

Abstract

We report on the phase diagram of antiferromagnetism (AFM) and superconductivity (SC) in three-layered Ba2Ca2Cu3O6(F,O)2 by means of Cu-NMR measurements. It is demonstrated that AFM and SC coexist uniformly in three-layered compounds as well as in four- and five-layered ones. The critical hole density pc for the long-range AFM order is determined as pc≃ 0.075, which is larger than pc≃ 0.02 and 0.055 in single- and bilayered compounds, and smaller than pc≃0.08–0.09 and 0.10–0.11 in four- and five-layered compounds, respectively. This variation of pc is attributed to the magnetic interlayer coupling, which becomes stronger as the stacking number of CuO2 layers increases; that is, the uniform coexistence of AFM and SC is a universal phenomenon in underdoped regions when a magnetic interlayer coupling is strong enough to stabilize an AFM ordering. In addition, we highlight an unusual pseudogap behavior in three-layered compounds—the gap behavior in low-energy magnetic excitations collapses in an underdoped region where the ground state is the AFM-SC mixed phase.

Source-reported materials — not catalogue approval

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