The magnetic behaviour of the magnetically diluted spinel compound Fe0.6Mg1.6Ni0.1Ti0.7O4 studied by Mössbauer spectroscopy

Mössbauer study of the re-entrant spin-glass behaviour in the mixed spinel ferrites Mg(0.9+x)Fe2(1−x)Ni0.1TixO4 (x=0.5 and 0.6)

“…This fits in with what has been found for the spin-glass sample with x = 0.7 [11]. It means further that the transversal relaxation only takes place on the B sites whereas the A sites have spins, which are mutually remaining parallel in a direction that is opposite to the average direction of the B-site spins.…”

“…The occurrence of magnetic clusters was further reported for various re-entrant SG systems [17,19] and one generally named these systems as ''cluster'' spin-glasses. In a previous work on the spin-glass Fe 0.6 Mg 1.6 Ni 0.1 Ti 0.7 O 4 [11], the present authors have established that the as-prepared sample shows typical SP features whereas after several times of reheating this sample the finally obtained material shows rather rigorous spin-glass behaviour. It is clear that the cluster behaviour of the as-prepared sample can be ascribed to non-homogeneity in the cation distribution within the sublattices, yielding magnetic clusters isolated from one another by diamagnetic cations.…”

“…From these distributions the concentration of magnetic cations on each sublattice can be calculated (C A and C B in Table 2). The investigated materials with x =0.5 and 0.6 together with the one with x= 0.7 [11] can now be represented in a phase diagram based on the magnetic concentrations on the sublattices (Fig. 8).…”

“…Table 1 Mössbauer parameters and canting data obtained from the 4 K external-field spectra for RH-samples with x= 0.5, 0.6 and 0.7 [11]. …”

“…When the tetrahedral sites (A) are fully occupied by magnetic cations or slightly magnetically diluted, the degeneracy is raised by a uniform A-B interaction resulting in a triangular Yafet-Kittel arrangement on the B sites. When, on the other hand, the A sites contain only a low amount of magnetic cations, the introduced topological disorder and the frustration due to the B-B and A-B antiferromagnetic interactions lead to spin-glass (SG) behaviour as has been reported for many strongly magnetically diluted spinel compounds such as Mg 1 [11] and some sulfospinels [12].…”