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 in creasing x. These increases depend on the difference: between the ioni c radii of the Ni2+ and the Cu2+ ions, The magnetic measurement indica tes that the 1/chi-T curve has a step caused by the mixture of the ant iferromagnetic cluster due to the 180 degrees superexchange interactio n far (Ni2+, Cu2+)-O-(Ni2+, Cu2+) and the paramagnetic spins. (C) 1998 Academic Press.