Structural, IR, and Magnetic Studies of Annealed Li-Ferrite Nanoparticles

A study of some properties for Li–Mn nanoparticles ferrite using positron annihilation lifetime technique

“…The flow chart of the preparation method is reported in ref. [8]. At room temperature using x-ray diffraction with CuK α radiation of λ = 1.54056 Å, the average lattice parameter is calculated for all investigated samples using the relation a = d hkl (h 2 + k 2 + l 2 ) (1/2) , where d hkl is the inter-planer spacing for a cubic crystal and h, k, l are the Miller indices of each plane.…”

“…K is a constant (0.9), β is the full width at each half maximum and θ is the corresponding diffraction angle [13]. The porosity percentage is calculated using Archimed's principle [8].…”

“…Below this value, the coercive field H c is directly proportional with the grain size in the single domain region. In this region, a nanoparticle assembly does not have a superparamagnetic behavior in an external magnetic field [8,9]. But, above H c critical value the coercive field is inversely proportional with the grain size for multi-domain ferrites and it reaches to zero for superparamagnetic rang (It has a bulk-like behavior) [10].…”

“…But, in the conventional method some Mn 3+ ions are formed at final sintering occupying octahedral sites. It is reported that the single domain critical size for Li-ferrite ≈ 74 nm, which corresponds to a maximum value of coercivity [8]. Below this value, the coercive field H c is directly proportional with the grain size in the single domain region.…”

Effect of Composition on Structural and Magnetic Properties of Nanocrystalline Ferrite Li0.5Sm x Fe2.5–x O4

“…Lithium ferrites can be synthesized by variety of techniques, such as high energy ball milling [22,23], solgel [24,25], auto-combustion method [25][26][27], solid state reaction [28][29][30], and co-precipitation [31]. To our best knowledge, the bulk magnetic properties of nanostructured LiSm ferrites, particularly synthesized by MA, have not been reported.…”