Lithium ferrite nanoparticles for ferrofluid applications

Nanoparticles of Lithium ferrite in the particle size range of 10nm have been prepared by a citrate precursor method at a relatively low temperature of 200°C. The particles show characteristic infra red (IR) spectrum of lithium ferrite and broadened X-ray diffraction (XRD) patterns typical of the nanoparticle nature. The sample decomposed at 200°C has the β-LiFe ₅O₈ type (a disordered type of spinel) structure which on annealing at 350°C transforms to the α-LiFe₅O₈ type (an ordered type spinel) structure as shown by both IR spectra and XRD studies. Magnetization curves indicate a particle size distribution consisting of both ferromagnetic particles and a superparamagnetic fraction. With 4ΠM_s values of 2000G these particles could be useful for applications in certain low magnetization ferrofluids.