Nickel-doped cobalt nanoferrites (Ni x Co 1-x Fe 2 O 4 , where x = 0.0 to 1.0 with step size 0.2) were prepared using the auto combustion method in which aloe vera extract was taken as a fuel. Further, characterization for antimicrobial, structural, optical, and magnetic studies was performed for the prepared ferrite nanoparticles. Antimicrobial activity was assessed against a prevalent human fungal pathogen, Candida albicans. The X-ray diffraction (XRD) pattern confirmed the spinel cubic phase with an average crystallite size of 28 nm. The Fourier transform infrared spectroscopy (FTIR) confirmed the stretching mode of vibration at the tetrahedral and the octahedral sites. Further, the analysis of magnetic properties was done using vibrating sample magnetometer (VSM), and the magnetic parameters, specific magnetization (67.69 emu/g) as well as squareness ratio σ R /σ S (0.47) were observed. From the UV-Visible absorbance spectra, the absorbance band edge was observed between 700 and 800 nm, and band gap values were observed at 2.84 eV for x = 1.0. Furthermore, the antimicrobial studies of the obtained ferrite nanoparticles were inspected against the C. albicans fungi, and it was observed that nickel-doped cobalt ferrite shows an inhibitory nature. Maximum inhibition of 0.43 (67% growth) was observed for the composition x = 1.0. Therefore, these ferrite nanoparticles can be used as a drug against fungus infection.aloe vera, Candida albicans, cobalt ferrite, nickel ferrite, XRD
| INTRODUCTIONFerrite nanoparticles get much more attention from researchers due to their unique chemical, optical, electrical and magnetic properties. [1][2][3][4] Spinel ferrites are the magnetic particles with the formula MFe 2 O 4 (whereas M represents Zn, Ni, Mn, Co, etc.) used in varied fields like magnetic sensing, data storage, ferrofluid, converters, magneto-optical recording, antennas, humidity sensors, energy storage devices, inductors, and microwave devices. [5][6][7][8] In the scientific world, magnetic nanoparticles attained more interest because of their valuable applications in medical fields like MRI, drug delivery, hyperthermia, ferrofluids, medical diagnostics, and cancer therapy. [9][10][11] The targeting and colloidal stability of nanostructure could be enhanced with the larger sensitivity of nanoparticles and this sensitivity depends on the ratio of surface area to the volume. 12 The nanoparticles have also been used for the waste water treatment and dye degradation property. [13][14][15][16] The properties of
