Structural and Electrical properties of M-type Nanocrystalline Aluminium substituted Calcium Hexaferrites

M-type calcium ferrites with substitution of Fe 3+ by Al were prepared by sol-gel auto-combustion technique by blending nitrates as oxidants accompanied with fuel s like urea as reducing agents. The powders were c hara terized using XRD and TEM. The XRD analysis indicated that e formation of single phase substituted M-type c alcium hexaferrites. The average particle size of the powd ers were close to 94 nm. The electrical conductivi ty of the synthesized samples was carried out by a four – pro be method in the same temperature range i.e. 300 K – 873 K. The value of ln( σ) of the samples decreases almost linearly with inc reasing reciprocal temperature upto transition temperature. The DC electrical resistivity of the s amples at room temperature was also increases with increase in the concentration of Al 3+ in the hexaferrite samples. The enhanced resistivi ty of the aluminium doped calcium hexaferrite is potential applicant in microwave dev ic s. The drift mobility of samples was calculated from the electrical resistivity data.