Magnetic structure of the metallic triangular antiferromagnet Ag2NiO2

The magnetic structure of the metallic antiferromagnet Ag2NiO2 with the Néel temperature TN = 56 K has been investigated by means of a neutron diffraction technique using a powder sample in the temperature range between 5 and 65 K. The antiferromagnetic (AF) diffraction peaks are clearly observed below TN and can be indexed with the propagation vector k=(1, 1/3 , 1/2 ). Based on the results of both a representational analysis and a Rietveld refinement of the magnetic peaks, the AF spin structure is determined as an A-type AF structure with ml = m0cos(2πk ⋅l), where ml is the moment at the lth Ni3+ site and m0 = (0.31,0,0.65) μB at 5 K. (paper)