Magnetism and superconductivity in 3d-metal-substituted Bi-based cuprates having the 2:2:0:1 structure

Abstract

The effects of the substitution for Cu or Mn by either a magnetic (Ni) or a nonmagnetic (Zn) 3d metal on the physical properties of the superconducting compounds Bi1.2Pb0.8La0.5Sr1.5CuO6+y and of the antiferromagnetic insulating phases Bi2Sr2MnO6+y and BiPbSr2MnO6, all isostructural to the 10-K superconducting Bi2Sr2CuOz (2:2:0:1) phase, have been investigated with use of x-ray powder diffraction, susceptibility, and resistivity measurements. We found that both Ni and Zn substitute for Cu and Mn with a range of solubility strongly dependent upon the nature of both the dopant and the host compound. For instance, in the Cu-based compounds the range of solubility is only a few percent (5% for Ni and 2% for Zn) whereas in the Mn-based compounds the range of solu- bility can be extended up to 20% for Zn or 30% for Ni. In the superconducting Bi1.2Pb0.8La0.5Sr1.5Cu1−xMxO6+y system, both Ni and Zn depress the Tc at approximately the same rate (8 K/mol %), so that the magnetism of the dopant has no effect on the Tc as observed for the other high-Tc cuprates. The Mn-based materials order antiferromagnetically and we found that upon substitution by Ni and Zn the antiferromagnetic transition temperature TN decreases less dramatically for the magnetic Ni [5 K/(10 at. %)] than for the nonmagnetic Zn [30 K/(10 at. %)]. A consideration of the exchange interactions can account for these results.

Source-reported materials — not catalogue approval

Similar papers