STRUCTURAL AND MAGNETIC PROPERTIES OF ALUMINUM SUBSTITUTED CoZr STRONTIUM NANOSIZE HEXAFERRITES
U. B. HATWAR *
Department of Engg. Science and Humanities (ESH), KITS, Ramtek, RTMNU, India
K. G. REWATKAR
Department of Physics, Dr. Ambedkar College, Nagpur, India.
V. M. NANOTI
Department of Applied Physics, PIET, Nagpur, RTMNU, India.
*Author to whom correspondence should be addressed.
Abstract
M type hexaferrite samples with chemical composition SrAlyCo0.2Zr0.2Fe11.6-yO19 where (y = 0,2,4) synthesized using proper stoichiometric proportions by microwave induced sol gel autocombustion route. The structural phase analysis was carried out by X-ray powder diffraction (XRD) method, which confirms the formation of the nanoferrite structure. It shows hexagonal magnetoplumbite (M) type structure having unit cell dimension ‘a’ and ‘c’ varies between 5-6 
and 21-23 . TEM analysis indicates that samples with grain size varies between 29 nm to 56 nm. Coercivity (Hc), saturation magnetization (Ms) and Retentivity (Mr) measurements were carried out by a vibrating sample magnetometer (VSM) with an applied field up to 15000 Oe. The Al3+ substitution enhances the coercive field. The saturation magnetization and Curie temperature decreases with substitution due to weakening of superexchange interaction.
Keywords: (CoZr)Sr ferrite, X-ray density, porosity, magnetization, coercivity, retentivity etc