Exploring nonlinear optical absorption in cobalt-doped Nickel-Zinc nanomaterials

This study emphasises on synthesis of ferrite nano powders via hydrothermal route within the compositional range of Ni 0 65 Zn 0.35 Co x Fe (2-2x/3) O 4 (x = 0.00 to 0.05 in steps of 0.01 wt%). Structural analysis via XRD and FTIR unveiled the cubic spinal structure, confirmed by signature absorption bands existence in the infrared spectra. The FESEM analysis revealed the morphological characteristics of ferrite crystals, while characterizations indicated a diminution in crystallite sizes from 53 to 37 nm. The magnetic behaviour displayed the existed correlation between Ms and Y-K angles along with finite size effects of the samples. Notably, low coercively values (0.13 Oe to 1.09 Oe) and magneto crystalline anisotropy pointed towards the magnetic quality of the ferrites with soft nature. Exhibited dielectric loss factor near 10 -1 , and ac -conductivity (sigma ac ) within the range of 10 - 5 S/m to 10 - 4 S/m of the samples indicates their improved dielectric properties. Further analysis from UV-vis. Diffuse reflectance (UV -DRS), PL spectroscopy, and Raman studies exhibits slight variations in optical band gaps, and vibrational modes due to varying cobalt doping concentrations. The evaluation of optical limiting characteristics using the Z -scan technique revealed absorption coefficients ranging from 1.40 to 4.80 x (10 -10 m/W) and onset limiting values between 1.93 W/m 2 and 1.11 W/m 2 . These findings position the Ni-Zn-Co ferrites as promising contenders for optical limiting applications owing to their optical nonlinearity and absorption characteristics.