Structural, elastic, thermal and soft magnetic properties of Ni-Zn-Li ferrites

The Ni0.6-xLi0.5xZn0.4Fe2+0.5xO4 (x = 0.0, 0.2, 0.4, 0.6) ferrites prepared by the sol-gel auto-combustion method have been characterized by XRD, XPS, SEM, FTIR, VSM, impedance analyzer for various physical properties. The analysis of Fe 2p photoelectron spectra reveals that the valence state of iron ion is only trivalent. The cation distributions obtained from Rietveld refinement of XRD data show that Li+ ions occupy only octahedral sites, while Ni2+, Zn2+ and Fe3+ ions are distributed in both tetrahedral and octahedral sites. The increase in bond angles (θ1 and θ2) suggests the enhancement of A-B super exchange interaction which is further confirmed by the decreased αY-K angles and increased Curie temperature (Tc). All observed absorption bands in the FTIR spectrum have been explained by the vibrations of tetrahedra and octahedra. The Debye temperature (θD) and the elastic moduli (bulk modulus B, rigidity modulus G and Young's modulus E) evaluated through FTIR spectroscopy decrease with the increase of Li+ and Fe3+ ions contents. The saturation magnetization (Ms) decreases firstly and then increases with x increasing. The initial permeability (μi) increases monotonically with x. The value of dielectric constant (ε′) sharply decreases at lower frequency and become almost stable at higher frequency for all samples, indicating the semiconductor behavior of the ferrites. Compared with the Li-Zn ferrite, the Ni-Zn ferrites has lower dielectric loss tangent (tan δε) and magnetic loss tangent (tan δm) at higher frequency. This work represents the first exploration of the correlation of structure with elastic, thermal and magnetic and electrical properties of Ni-Zn-Li ferrites. •The cation distributions are obtained from Rietveld refinement of XRD data.•The calculated bond angles and αY-K angle confirm the increase of A-B interaction.•The Debye temperature and elastic moduli are evaluated through FTIR spectroscopy.•The change of saturation magnetization can be explained by cation distributions.•The initial permeability increases with increasing Li+ and Fe3+ contents.