Magneto Optical Properties and Hyperfine Interactions of Cr3+ Ion Substituted Copper Ferrite Nanoparticles

Spinel CuCrxFe2-xO4 (0.0y1.0) nanoparticles were fabricated by co-precipitation. X-ray diffraction proved the pureness and cubic crystal assembly of products which have the crystallite sizes varying between 16 and 33nm. The cubic morphology and expected chemical composition, spectral analyses of all sample were accomplished via Scanning electron microscopy along with Energy Dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy respectively. Magnetic and optical characterization of samples were done via Vibrating sample magnetometer, Mossbauer spectroscopy and Diffuse reflectance spectroscopy. Kubelka-Munk model was applied to UV-Vis data for calculating the optical Eg (band gap) values between minimum 1.20 and maximum 1.80eV. Mossbauer analysis determined the consequence of Cr3+ substitution on isomer shift and quadrupole splitting of all products etc. The specific magnetization (sigma-H) hysteresis curves have finite coercivity (in a range of 35-410Oe) and retentivity (in a range of 0.33-3.84emu/g) values and reveal the soft ferrimagnetic nature of spinel CuCryFe2-yO4 nanoparticles (NPs). The estimated saturation magnetization M-s value of 35.17emu/g is maximum for pristine CuFe2O4 NPs and decreases to minimum value of 1.57emu/g for CuCr0.4Fe1.6O4 NPs due to Cr3+ ion substitution. The calculated squareness ratios less than 0.5 assign the uniaxial anisotropy for all CuCryFe2-yO4 NPs. The magneto-crystalline anisotropy field (H-a) values less than 10.0kOe except for the composition of CuCr0.2Fe1.8O4 NPs are other magnetic data to reveal the soft magnetic character of samples.