Microstructure and Magnetic Properties of Spinel Ferrites

Abstract

Achieving suitable magnetic properties in ceramic ferrites through thermomechanical treatments rather than through varying the processing and fabrication parameters alone are investigated. The high temperature phase transformation in lithium ferrite (LiFe5O8) spinel and the defects in LiFe5O8 and NiFe2O4 are studied using high voltage transmission electron microscopy in an effort to characterize the microstructures. Results show that a dispersion of paramagnetic LiFeO2 particles in LiFe5O8 matrix gives rise to increased squareness of the hysteresis curve and increased coercivity. Annealing treatments of sintered ferrites remove undesirable intra‐granular {100}1/4〈110〉 cation stacking faults and improve hysteresis loop parameters.