Three-dimensional magnetic properties of Bi₂CuO₄

Abstract

Magnetic susceptibility and neutron diffraction measurements prove the 3D rather than the 2D or 1D character of magnetic interactions in Bi2CuO4. It has been shown that, at TN=44.6+or-0.3 K, Bi2CuO4 undergoes a transition to an antiferromagnetic state. The magnetic unit cell coincides with the chemical cell (k=0) and is of type I. The value of magnetic moment is either (0.53+or-0.1) mu B or (0.75+or-0.1) mu B depending on whether the magnetic moments are oriented parallel or perpendicular, respectively, to the c axis. The effective magnetic moment of the Cu2+ ion is (1.80+or-0.2) mu B. The results of theoretical susceptibility calculations for the BCT lattice model and for the SQ lattice model together with the molecular-field interactions have been presented and compared with the experiment.