Authors : P. R. Moharkar, S. R. Gawali, R. R. Kherani, K. G. Rewatkar
Page Nos : 57-68
Description :
Hexaferrites are industrrially important materials that have numerous technological
applications such as permanent magnets, microwave devices, magnetic recording media and
magneto-optical devices. Keeping this view, the nanocrystalline aluminium substituted
calcium hexaferrites CaAlxFe12-xO19 (x = 3; 6) have been synthesized using sol-gel autocombustion
technique by blending metal nitrates as oxidants accompanied with fuel like urea
as reducing agent. The synthesized samples were characterized using XRD, TEM and VSM.
XRD study showed that the synthesized samples were single M-type hexagonal ferrites. The
effect of substitution of Al3+ ion for Fe3+ ion on the unit cell parameters, density and porosity
has been studied. The TEM study showed that the average particle size of the synthesized
samples was close to 94 nm. The DC electrical conductivity was measured as a function of
temperature from 300 K to 873 K using two probe techniques. The phenomenon of conduction
was explained on the basis of a Vervey hopping model. The magnetic study reveals that the
substitution of Al3+ ion for Fe3+ ion in calcium hexaferrite greatly improves the magnetic
parameters.
