Mössbauer and magnetic studies in nickel ferrite nanoparticles: Effect of size distribution

Crystallization and magnetic behavior of nanosized nickel ferrite prepared by citrate precursor method

“…We found that H c decreases almost linearly with increasing T in which the H c value at T = 300 K is 60% of the value at T = 5 K. The H c value in this particular case is influenced by various factors arising primarily from the broad particle size distribution and their temperature-dependent characteristics are difficult to be separated from one and another. According to previous works [11,12], the particle size limit below which nickel ferrite is in the single domain state is around 35 nm, our sample therefore contains both types of single and multi domain particles in which the latter has a larger volume fraction (Fig. 3).…”

“…The variation of the saturation magnetization at low temperature range also account for the finite size effect and surface contribution which is manifested via modified Bloch law's behavior for spin waves [10]. In order to tailor the size, morphology and magnetic properties of the nickel ferrite nanoparticles different preparation techniques have been used such as sol-gel [11], reverse micelle [7], aerosol [12], co-precipitation [10] and mechanical milling [9]. In this paper, the preparation of nickel ferrite nanoparticles by a citrate precursor gel formation route at moderate temperatures and its characterization by DTA/TG, XRD, TEM and magnetic measurements are presented.…”

The effect of annealing on microstructure and cation distribution of NiFe2O4

“…It was expected that increase in the grain size caused the increasing values of saturation magnetization. According to [35,36] larger grains tend to consist of more magnetic domains, therefore the magnetization caused by domain wall movement requires less energy. Contrary, small grains tend to have a simpler domain structure, towards a single-domain state below a critical size and therefore, more energy is required for its domain rotation.…”

Exchange spring like magnetic behavior in cobalt ferrite nanoparticles

“…The physical properties of these nanoparticles can also be easily tailored by controlling its microstructure and enabling them for many applications [13][14][15]. The sizes of the nanoparticles [14,16], morphology [7,13], size distribution [17][18][19], packing density [20], intergranular exchange interaction [21][22][23], and cation distribution [24,25] are some of the factors which are responsible for the modified magnetic properties in the nanomaterials. Among these, grain/particle size and their distributions are most of the important factors governing the magnetic properties in the nanomaterials.…”