Investigation of the magnetic structure of the spinel compound ZnxCu1-xFeCrO4 by neutron diffraction

Temperature-dependent neutron diffraction measurements have been performed on the spinel system ZnxCu1-xFe-FeCrO4 prepared by the ceramic sintering method. The system shows significant deviations front the usual ferrimagnetic behavior. The ferrimagnetic order is perturbed due to the presence of non-collinear spins mainly at the B site, For compositions with larger x values. an unstable ferromagnetic transition takes place before reaching the paramagnetic state, The system may be said to be in a perturbed ferrimagnetic state at xless than or equal to0.4, where ferrimagnetic ordering is perturbed by the presence of locally canted spin components. The presence of small fluctuating magnetic clusters superimposed on the ferrimagnetic Iona range order has been revealed by the features shown by neutron data from the compositions with xgreater than or equal to0.6, For x = 0.6. the lowest-Q Bragg reflection is significantly broadened by the diffuse scattering from these Clusters. A semi-spin glass state is proposed for the composition with x = 0.6. while a drastic reduction of the sublattice magnetization and a decrease of the diffuse signal is in favor of a cluster spin glass-like phase for the specimen with x = 0.8. (C) 2002 Elsevier Science B.V. All rights reserved.