Polycrystalline samples of mixed ferrites Cd(0.5)Co(0.5+t)A(t)Fe(2-2t)O(4),
where A = Si or Ti and t = 0.0, 0.1, 0.2, 0.3 and 0.4 were prepared by cer
amic processing. X-ray analysis showed that the lattice constant increases
with increasing Ti whereas it decreases with increasing Si. The saturation
magnetization (M-s) decreases slowly for t less than or equal to 0.2 Ti and
afterwards rapidly. In the case of Si-substitutions, the M-s increases sli
ghtly for x less than or equal to 0.2 and then decreases. The M-s value is
higher for the case of Si-substitutions than that of Ti ones. The Curie tem
perature (T-c) decreases with t in case of Ti and increases in case of Si.
The initial permeability (mu(i)) increases slowly for t less than or equal
to 0.2, and suddenly for t > 0.2 for Ti. In case of Si-substitutions the mu
(i) continuously decreases with t. Permeability with frequency showed dispe
rsion behaviour. Relaxation frequencies shift to lower value in case of Ti
and to higher value in case of Si-substitution. The variation in permeabili
ty is explained on the basis of single ion model. (C) 1999 Kluwer Academic
Publishers.