Preparation Of Polycrystalline Ga_xFe_2-xO₃by Chemical Method And Study Of Its Properties

Magnetic materials are important functional materials, which are indispensable inelectronic technology, communication technology and other fields. Iron oxide is a kind ofimportant magnetic material, it has such advantages as stable chemical properties and highcatalytic activity, it has a wide range of applications in practical production. With therapid development of high-tech, single Fe2O3particles cannot satisfy the urgent needs ofthe synthesis of new materials, so gallium doped Fe2O3, which have different physicalproperties, have aroused the attention of researchers. Gallium doped Fe2O3have differentnature such as crystal structure, magnetic properties and optical band gap, which arecontrollable and more applicable.In this experiment, a series of polycrystalline GaxFe2-xO3(0≤x≤2) compounds havebeen prepared by combination of reverse micelle and sol-gel methods, the particles werecrystalline and well dispersed. With the increase of the doping amount of gallium, wehave obtained samples of three crystal structures, α phase, β phase and ε phase. Due to thedoping of Ga, the raman active modes of the sample show raman frequency shiftphenomenon. The magnetic properties such as magnetic hysteresis behavior, magneticphase transition temperature and the magnetization intensity change with the increase ofgallium.In our work, When the doping amount of gallium is small (0≤x≤0.5), GaxFe2-xO3samples are well stabilized in α phase, which have the same crystal structure with α-Fe2O3(rhombohedral structure), magnetic frustration effect exists in the samples, TM(x=0) isgreater than TM(x=0.1), when x≥0.2, morin temperature disappear. With the increase ofthe magnetic field, Tirr decreases. When the doping amount of gallium is comparativewith the amount of iron (0.8≤x≤1.4), GaxFe2-xO3samples have the same crystal structurewith GaFeO3(orthorhombic structure), Curie temperature Tc, thermomagnetic irreversibletemperature Tirr decrease with the increase of the gallium, Tirr decrease with the increaseof the magnetic field, while Tc remains unchanged, magnetic frustration effect exists inthe samples. Hc and Mr are large.When the doping amount of gallium is large (1.6≤x≤2.0),GaxFe2-xO3samples have the same crystal structure with β-Ga2O3(monoclinic structure), the magnetic intensity is low. The optical band gap of α、ε and β phase samples increasewith the increase of doping amount of gallium.