Study of the influence of thermal treatment on the magnetic properties of lithium ferrite prepared by wet ball-milling using nitrates as raw material

• The saturation magnetization increases with heat-treatment temperature until 1200 °C.
• 1200 °C sample presents, at 5 K, a magnetic moment of 73 emu/g and 66 emu/g at 300 K.
• Heat-treatment promotes the formation of lithium ferrate and hematite, decreasing the magnetic moment.

Lithium ferrite (LiFe5O8) is an attractive material for several potential technological applications. Critical to such attractiveness are its physical properties, such as high Curie temperature, square hysteresis loop and high magnetization. Knowing that the properties of these crystals depend on the preparation method and raw materials, in this work LiFe5O8 crystallites were obtained by controlled heat-treatments, between 200 and 1400 °C, of homogeneous Li2O-Fe2O3 powders prepared by wet ball-milling method and using lithium and iron nitrates as raw materials. LiFe5O8 crystal phase was formed through heat-treatments at temperatures above 500 °C. At higher temperatures the formation of lithium ferrate and hematite is promoted, leading to a decrease in the magnetic moment. Heat-treated the sample at 1200 °C results in the highest levels of magnetic saturation, presenting a magnetic moment of 73 emu/g at 5 K and 66 emu/g at 300 K, respectively.

Figure optionsDownload as PowerPoint slide