Magnetic susceptibility of the normal state in oxygen-controlled Ca-rich Bi-2212 cuprate

Abstract

We have studied the normal-state magnetic susceptibility and the crystal structure in Ca-rich Bi-2212 cuprate (Bi 2.18Sr 3− x Ca x Cu 2O y ( x=1.0, 1.2, 1.4, 1.6)). The carrier density of each sample was changed by the oxygen content. The normal-state susceptibility data were fitted to Johnston's universal curve which gives some physical parameters including T max where the normal-state susceptibility gives maximum, the temperature-independent part of the normal-state susceptibility χ 0, and the maximum susceptibility χ 2D max at T max. From χ 0 we can estimate Pauli paramagnetism χ Pauli proportional to the density of states at Fermi surface. We have found that both T max and χ 2D max are independent of Ca content in contrast to a previous report, but dependent on χ Pauli and the dependence changes at some value of χ Pauli.