Crystal structure and magnetic properties of (Ni6-xCux)MnO8

Murdochite-type (Ni6-xCux)MnO8 (0.0 less than or equal to x less than or equal to 0.4) was synthesized at 873 K using the precursor method. Both the (Ni, Cu)-O(1) and Mn-O(1) distances increase slightly with increasing x. These increases depend on the difference: between the ionic radii of the Ni2+ and the Cu2+ ions, The magnetic measurement indicates that the 1/chi-T curve has a step caused by the mixture of the antiferromagnetic cluster due to the 180 degrees superexchange interaction far (Ni2+, Cu2+)-O-(Ni2+, Cu2+) and the paramagnetic spins. (C) 1998 Academic Press.