Magnetic properties of (Bi, Pb) sub(2)(Sr, La) sub(2)(Ln, La) sub(2)Cu sub(2)O sub(z) (Ln identical with Sm, Eu, Gd, Dy)

SQUID and ESR measurements were performed for (Bi, Pb) sub(2)(Sr, La) sub(2)(Ln, La) sub(2)Cu sub(2)O sub(z) (Ln identical with Sm, Eu, Gd, Dy) heat-treated under a high pressure of oxygen, and their magnetic properties were investigated. A weak diamagnetic magnetization due to superconductivity was observed in a temperature range below 44-46 K, and its magnetic susceptibility was determined as - (1.2 - 2.0) x 10 super(-4) at 5 K under the static magnetic field of 5 kOe. Further, a weak or short-range antiferromagnetic order was observed even at room temperature in paramagnetic (Bi, Pb) sub(2)(Sr, La) sub(2)(Gd, La) sub(2)Cu sub(2)O sub(z), and its temperature variation was investigated. The exchange field between Gd super(3) spins was concluded to be larger than 3 kOe at room temperature.