It is well known that when ferrites are sufficiently diluted with non-magnetic atoms they can show a wide spectrum of magnetic structures: ferrimagnetic order, cluster spin glass, etc. [1]. Recently a tentative phase diagram has been proposed [1] to classify the different substituted ferrite compounds. The presence of Mn 3+, Fe 2+ or Co 2+ in the ferrite system introduces an additional factor (i.e. uniaxial anisotropy [2]) which increases the possible magnetic structures and thus changes the above-mentioned phase diagram [1].
The system under investigation, ZnzCoTi z Fe2_x_zCrx_z04, contains the anisotropic magnetic ion Co 2÷, of which the ferrimagnetic phase has been modified substituting Fe 3÷ ion with non-magnetic Zn 2--and Ti 4÷ and magnetic Cr 3+ so that the intrasublattice interactions become more predominant than inter-sublattice interactions, leading to frustration in the spin system. In view of this the magnetic properties of the ternary spinel system ZnzCoTi z Fe2_x_zCrr_zO 4 for x = y = 0.65, 0.70 and 0.80 with z=x.y, are investigated. No measurements have previously been reported in the literature. In this letter we report the results of a.c susceptibility, d.c. magnetization and Mossbauer measurements on the spinel system ZnCoTiFeCrO.
The three samples of the ZnCoTiFeCrO system were prepared by the usual double sintering ceramic method for x = 0.65, 0.70 and 0.80. The starting materials were Fe203, CoO, ZnO, Tio2 and Cr203, all 99.9% pure and supplied by E. Merck. The X-ray patterns of all the ferrite samples were recorded using FeK~ radiation on a Philips PM 9220 X-ray diffractometer and the diffractograms showed sharp