Tuning of magnetic properties of Al-doped cobalt ferrite nanofiber prepared by electrospinning technique

Abstract The Al-doped cobalt ferrite (CoFe 2-x Al x O 4 ) nanofiber has been prepared by employing the electrospinning technique. All the nanofibers are characterized by the XRD technique. The Rietveld refinement of the XRD pattern reveals the spinel cubic structure with the Fd 3 ¯ m space group. The TEM micrographs confirm the formation of nanofiber with a nearly uniform diameter of ∼137 ± 10 nm. The magnetic properties of all the nanofibers have been investigated by measuring the M-H hysteresis loops with the help of a Vibrating sample magnetometer (VSM). The M-H loops analysis demonstrates a reduction in the saturation magnetization, and coercivity from 106.88 emu g −1 to 40.01 emu g −1 and 0.897 kOe to 0.324 kOe, respectively, with the increase in Al concentration in the nanofibers. The ‘Law of Approach to Saturation’ technique has been employed to understand the magnetocrystalline anisotropy constant in the samples. The magnetocrystalline anisotropy constant ( K 1 ) decreases with the increase in Al 3+ substitution in place of Fe 3+ in the spinel cobalt ferrite nanofibers. A squeezing effect on the M-H loop near M = 0 is observed and, it has been analyzed by a hysteresis loop width ( ∆H ) versus magnetization ( M ) plot. The squeezing effect has been observed due to the exchange interaction phenomenon between the magnetic and non-magnetic atoms in the Al-doped cobalt ferrite nanofiber. The magnetic properties study demonstrates that Al-doped cobalt ferrite nanofiber exhibits soft magnetic nature.