Structure-Property Correlations of Carbon and Nitrogen Incorporated NiFe<inf>2</inf>O<inf>4</inf>

In this paper, carbon (C) and nitrogen (N) were incorporated into the interstitial sites of nickel (Ni) ferrite lattice. Structural studies of the incorporated NiFe2O4 (NFO) samples (C-NFO and N-NFO) using X-ray diffraction revealed changes in the values of the lattice parameter, bond angle, and bond length. Raman spectroscopic studies revealed shifts in peak positions of Eg and T2g(3) vibrational modes of the spectra. Magnetization measurements at 20 and 300 K using vibrating sample magnetometer showed decrease in the values of Ms} upon incorporation of C/N (2.3 μB/f.u. of C-NFO and 2.4 μB /f.u. of N-NFO from 2.9 μB/f.u. of NFO, at 20 K). An increase in intrinsic coercive field (Hc) value (18.2 Oe of C-NFO and 14.2 Oe of N-NFO from 5.2 Oe of NFO, at 20 K) was also observed. However, a reduction in the value of first-order cubic magnetocrystalline anisotropy constant (K1) was observed upon incorporation of C/N. Microstructural analysis using scanning electron microscopic images revealed modifications in the shape and the size of the grains. The average grain size was found to be reduced upon C/N incorporation (~600 nm of NFO, while 550 nm of C-NFO and ~400 nm of N-NFO).