Li0.5Fe2.5-xMnxO4 ferrite sintered from microwave-induced combustion

Li0.5Fe2.5-xMnxO4 (0 <= x <= 1.0) powders with small and uniformly sized particles were successfully synthesized by microwave-induced combustion, using lithium nitrate, ferric nitrate, manganese nitrate and carbohydrazide as the starting materials. The process takes only a few minutes to obtain as-received Mn-substituted lithium ferrite powders. The resultant powders annealed at 650 C for 2 h and were investigated by thermogravimeter/differential thermal analyzer (TG/DTA), X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermomagnetic analysis (TMA). The results revealed that the Mn content were strongly influenced the magnetic properties and Curie temperature of Mn-substituted lithium ferrite powder. As for sintered Li0.5Fe2.5-xMnxO4 specimens, substituting an appropriate amount of Mn for Fe in the Li0.5Fe2.5-xMnxO4 specimens markedly improved the complex permeability and loss tangent. (c) 2004 Elsevier Ltd. All rights reserved.