Magnetic properties of Ni-doped Sr2CuO3

Abstract

We report the effects of doping Ni (S = 1) in place of Cu (S = 1/2) in the quasi-one-dimensional Heisenberg antiferromagnetic (1DHAF) chain compound Sr2CuO3. For the low doping levels considered here, Sr2Cu1-xNixO3 (0 less than or equal tox less than or equal to0.03), the lattice parameters do not change significantly upon doping. The magnetic susceptibility chi (ratio of the magnetization M to the applied field H) is found to have a Curie-like dependence at low temperatures. While the Curie constant Cw is found to increase with Ni doping, its magnitude is considerably smaller than expected from isolated S=1 Ni magnetic moments. This would seem to arise from the unusual nature of the ground state of the S=1/2 1DHAF compound Sr2CuO3.