Magnetic phase diagram of hole-doped Ca2-xNaxCuO2Cl2 cuprate superconductor

We report on the magnetic phase diagram of a hole-doped cuprate Ca 2- x Na x CuO 2 Cl 2 , which is free from buckling of CuO 2 planes, determined by muon spin rotation and relaxation. It is characterized by a quasi-static spin-glass-like phase over a range of sodium concentrations (0.05≤ x ≤0.12), which is held between the long-range antiferromagnetic (AF) phase ( x ≤0.02) and the superconducting phase where the system is nonmagnetic for x ≥0.15. The obtained phase diagram qualitatively agrees well with that commonly found for hole-doped high- T c cuprates, strongly suggesting that the incomplete suppression of the AF order for x > 0.02 is an essential feature of the hole-doped cuprates.