Synthesis, structural and magnetic behavior studies of Zn–Al substituted cobalt ferrite nanoparticles

• Zn–Al substituted cobalt ferrites were prepared by co-precipitation method.
• The effect of Zn–Al substitution on structural and magnetic properties were studied.
• X-ray diffraction patterns reveal pure spinel structure and the maximum crystalline size was 30.67 nm.
• These nanocrystalline were small enough to obtain the suitable signal to noise ratio in high density recording media.
• The values of Ms, Hc and Mr were found to be strongly affected by the Zn–Al contents.

A series of nano-sized Zn–Al substituted cobalt ferrite Co(1−x)Zn(x)Fe2−xAlxO4 with 0.0⩽x⩽1.00.0⩽x⩽1.0 have been synthesized by chemical co-precipitation technique. The XRD spectra revealed the single phase spinel structure of Co(1−x)Zn(x)Fe2−xAlxO4 with average size of nanoparticles are estimated to be 17–30 nm. These are small enough to achieve the suitable signal to noise ratio, which is important in the high-density recording media. The FTIR spectra show the characteristic of two strong absorption bands at 560–600 cm−1 corresponds to the intrinsic stretching vibrations of the metal at the tetrahedral site and lowest band is observed at 370–410 cm−1 corresponds to octahedral site. The crystalline structures of nanoparticles composite were characterized by Field Emission Scanning Electron Microscopy (FE-SEM). The magnetic properties such as saturation magnetization, remanence magnetization, and coercivity were calculated from the hysteresis loops. Saturation magnetization were found to increase up to x = 0.4 while remanence magnetization and coercivity continuously decrease with increasing Zn–Al concentration. The stability in coercivity while increase in saturation magnetization confirms that the Co0.6Zn0.4Fe1.6Al0.4O4 ferrite sample is suitable for applications in high-density recording media.