Study of Structural and Magnetic Properties of Ni Substituted M Type Calcium Hexaferrite

Abstract

Ni substituted M type calcium hexaferrite with composition CaNi_xFe_12-xO₁₉ (x = 0.5, 1.0, 1.5, 2.0) were synthesized by sol - gel auto combustion method. X-ray diffraction analysis confirms the phase composition of prepared samples and reveals that all the samples belong to M type hexaferrite. The crystallite size was determined by the Debye Scherrer formula and W-H Plot analysis method. Lattice parameters (‘a’ and ‘c’) and lattice volume increases with increase in Ni²⁺ ion concentration. Morphology of the samples was observed by scanning electron microscopes showing that all the prepared samples were hexagonal structure. The absorption band between 516 cm⁻¹–527 cm⁻¹ and 427 cm⁻¹–462 cm⁻¹ in the FTIR study confirms the formation of hexaferrite. With increasing Ni²⁺ ion concentration the peak position in FTIR and XRD was shifted toward lower frequency and lower angle. Energy-dispersive X-ray spectroscopy analysis confirms the presence of Fe, Ca, Ni and O in all the samples. Vibrating sample magnetometer was used to measure the magnetic parameters such as saturation magnetization, coercivity and remanent magnetization. Saturation magnetization increases from 8.845 emu/gm to 26.05 emu/gm, while the coercivity increases from 162.88 Oe to 184.67 Oe with increasing Ni²⁺ ion concentration from 0.5 to 2.0 make substituted hexaferrite material suitable for recording media.[AQ1]

Keywords:

• -Ni substituted calcium hexaferrite
• sol-gel auto combustion method
• magnetic properties
• energy-dispersive X-ray spectroscopy
• Fourier transform infrared spectroscopy

Acknowledgments

The authors wish to acknowledge SAIF, IIT Madras for providing characterization facilities.