Synthesis and study of dielectric and magnetic properties of aluminum lithium and nickel doped strontium hexaferrites nanoparticles.

Abstract

In the present study synthesis of strontium hexaferrites with chemical compositions SrFe12O19 and SrFe12-2x (Al, Li, Ni) x O19 was performed by sol gel method. Initially pure strontium hexaferrites with chemical composition SrFe12O19 was synthesized and then doped strontium hexaferrites with chemical composition SrFe12-2x (Al, Li, Ni) xO19 was synthesized with variation in dopants’ concentration from x=0, 0.2, 0.35 and 0.5. Stiometric amount of strontium, iron, aluminum, lithium nickel nitrates and citric acid along with ammonia solution to maintain pH of solution were used to prepare sample. The characterization was performed using X-ray diffraction technique and Fourier transform infrared spectroscopy. The electrical properties were examined by using RF Impedance analyzer and magnetic properties were examined using Vibrating sample magnetometer. Crystallite size was calculated by Debye Scherrer formula which came out in the range of 27nm to 35nm.By dielectric properties measurement an increase in dielectric constant, dielectric loss and tangent at low frequency and started to decrease at higher frequencies and eventually became constant. This effect had been correlated to the impact of grain boundaries at low and high frequency. Magnetic properties measurement was performed by using vibrating sample magnetometer that revealed that the saturation magnetization decreased with the increase in dopants’ concentration due to accumulation of cations at interstitial sites with upward spin. Coercivity also decreased with increasing dopant concentration giving rise to the impact that the material is moving towards being softer.