Influence of synthesis approach on structural and magnetic properties of lithium ferrite nanoparticles

► Nanocrystalline Li0.5Fe2.5O4 ferrites were synthesized with an average crystallite size of 12.3nm and 5.7nm by chemical co-precipitation and reverse microemulsion technique respectively. ► The non-saturated M–H loops, absence of hysteresis, remanence and coercivity at room temperature is indicative of the presence of superparamagnetic and single-domain particles for both the materials. ► The blocking temperature TB shifts to lower temperature with the increase of applied field, which is attributed to the reduction of magnetocrystalline anisotropy constant. ► At high temperature, microemulsion synthesized nanoparticles are observed to show a maxima immediately below the Curie temperature which is attributed to the cumulative effect of the anisotropy variation of temperature and particle size growth during the measurement. Nanocrystalline Li0.5Fe2.5O4 ferrite particles were synthesized with an average crystallite size of 12.3nm and 5.7nm by chemical coprecipitation and reverse microemulsion technique respectively. Zero-field cooled (ZFC) and field cooled (FC) magnetization measurements at different magnetic fields and magnetic hysteresis loops at different temperatures have been measured. The non-saturation of M–H loops with a very low coercivity and remenance at room temperature confirms the presence of superparamagnetic (SPM) nature and single-domain ferrite particles. The blocking temperature (TB) has been found to shift towards the lower temperature region with the increase in applied magnetic field. It has been attributed to the reduction of magnetocrystalline anisotropy constant and blocking temperature dereases from 145K to 110K with increase in field from 50Oe to 1000Oe in the samples synthesized by microemulsion method. At high temperature, microemulsion synthesized nanoparticles show a maximum in magnetization versus temperature plot just below the Curie temperature (TC) which has been attributed to the cumulative effect of the change in anisotropy with temperature and particle size growth during the measurement.