Mssbauer Spectrum And Magnetic Property Analysis On Doped Lithium Ferrite

Lithium ferrites is one of the soft magnetic material that is widely used, because of its high Curie temperatures, electrical resistivity, saturation magnetization, strong magneto-crystalline, as well as smaller magnetostriction coefficient and low-cost, which has been widely used in computer core, microwave devices, electromagnetic wave absorption and shielding, and other fields. However, how to prepare lithium ferrite which has excellent properties has become a hot issue. In this paper, lithium ferrite powders were obtained by the sol-gel auto-combustion method, and to dope modification research, nonmagnetic ions (Li+ ions and Al3+ ions) was selected. Then the lithium zinc ferrite was doped by Gd3+. Structures and magnetic properties of all samples were characterized by Thermogravimetric Analysis-differential scanning calorimetry (TG-DSC), X-Ray Diffractometer (XRD), Scannning Electron Microscope (SEM), Superconducting Quantum Interference Device (SQUID) and Mossbauer Spectrometer. The main research works are as follows:1. Non-magnetic Zn2+ ions substituted Li0.5Fe2.5O4 ferrites were studied. The XRD analysis showed that the samples are cubic spinel ferrite, and the lattice parameter increased with Zn2+ ions concentration increasing. The SEM analysis showed that particle size decreased and the aggregates were improved. The SQUID analysis showed that the saturation magnetization were firstly increased and then decreased with Zn2+ ions concentration increasing. The Mossbauer Spectrum analysis showed that with Zn2+ ions concentration increasing ferromagnetic phase gradually transformed into a paramagnetic phase.2. Magnetic Gd3+ ions substituted Li0.35Fe2.35Zn0.3O4 ferrites were studied. The XRD analysis showed that the samples are cubic spinel ferrite, the lattice parameter increased and the average grain size decreased with Gd3+ ions concentration increasing. The SEM analysis showed that particle sizes were uniform and good dispersion, and the particle size decreased with Gd3+ ions concentration increasing. The SQUID analysis showed that the saturation magnetization of samples decreased with Gd3+ ions concentration increasing. The Mossbauer Spectrum analysis showed that ferromagnetic phase gradually transformed into a paramagnetic phase with Gd3+ ions concentration increasing.