Influence of the cation distribution on the magnetization of Y-type hexagonal ferrites

Moessbauer absorption and magnetization measurements have been made in Mg2 - Y and Co2 - Y ferrites. The magnetizations of the various iron sublattices did not show any marked difference in Mg2 - Y, whilst in the case of Co2 - Y three different behaviours of the sublattice magnetizations have been detected. Low-temperature magnetization measurements in Mg2Y gave evidence of a non-collinear magnetic order. The different magnetic properties of these compounds have been explained on the ground of a preferential occupation by Mg2+ and Co2+ ions of the inner octahedral sites of the T crystallographic block. The presence in these sites of a non-magnetic ion such as Mg2+ is responsible for the peculiar magnetic order observed in Mg2 - Y. (orig.)