The effects of Cr substitution on the structural, elastic, electrical and magnetic properties of \(Li_{0.3} Cr_{x} Zn_{0.4} Fe_{2.3 - x} O_{4}\) (where x = 0.0, 0.1, 0.3 and 0.5) compositions have been studied along with the microstructural features. The crystal structure has been observed with an X-ray diffraction technique and it confirms a single-phase cubic spinel structure without any impurity peak. The lattice constant, tetrahedral (A-site), and octahedral (B-site) bond lengths have been calculated and all the parameters decreased with an increase in Cr content due to a shortening of the unit cell. Fourier transforms infrared (FTIR) analysis shows that the characteristic peaks are found in the range from 532 to 584 cm−1 due to the stretching vibrations at the A-site, and in the range from 354 to 365 cm−1 due to the bending vibration in the B-site, respectively. The elastic properties analysis indicates that the synthesized samples are in ductile nature. The microstructural study shows that the average grain diameter is found to be larger for x = 0.1, which could be attributed to the densification of the sample. An enhancement of initial permeability is clearly observed at x = 0.1, which is correlated to the larger grain size. The M-H curve demonstrates that the saturation magnetization reduces linearly as the content of Cr increases from x = 0.0 to x = 0.5. This could be ascribed to the reduction of A-B exchange interaction. Dielectric constant (ε′) and ac electrical conductivity ( \({\sigma }_{ac}\) ) have also been enhanced for x = 0.1. However, both ε′ and \({\sigma }_{ac}\) reduced for x \(>\) 0.1, which might have diluted the electron exchange between Fe2+ and Fe3+ due to the strong occupancy of Cr3+ ions at the B-site. In addition, Cr substituted Li–Zn ferrite samples (for x \(>\) 0.1) show higher frequency stability compared to a pure system.
