Magnetic Property of α-Fe₂O₃Nanoparticles Prepared by Sonochemistry and Take-off Technique

Abstract

A new synthetic method for the formation of uniform α-Fe 2 O 3 nanoparticles was reported and their magnetic properties were investigated. The sonochemical synthesis and the subsequent takeoff technique resulted in spherical shaped α-Fe 2 O 3 nanoparticles with an average diameter of 60 nm. The temperature-and applied magnetic field-dependent magnetization of the α-Fe 2 O 3 nanoparticles was explained by the sum of two contributions, i.e., the Morin transition and superparamagnetism, because the critical size for superparamagnetism was within the size variation of the nanoparticles.

Attempts to obtain BaTiO3/Fe2O3 core-shell type structures: The role of iron oxide nanoparticle formation and agglomeration

“…[41] these grain diameters for these two samples were estimated, as 28.4 nm and 60.6 nm, respectively. Similar behavior to the BTF4 and BTF5 samples was reported in [53], where both the blocking process and the Morin phase transitions were observed for hematite nanoparticles with the diameter range 35 < d < 85 nm. It can therefore be concluded that, the BTF4 and BTF5 samples have wide grain diameter distributions, and even double distributions, where smaller nanoparticles exhibit the collective blocking process, while grains with the average size predicted in the above estimation undergo the Morin transition.…”

“…Also, the magnetic properties of hematite are not indifferent to the crystallinity of the samples, or the final shape and the surface structure of the grains [41][42][43][44][45][46][47][48][49][50]. Granular hematite systems, depending on the average dimensions of particles, d, may exhibit for T < T M only the Morin transition [51,42,52,[46][47], the Morin transition and the superparamagnetic (SPM) [46,53], or only the SPM state [38,[45][46][47][54][55][56]. It is well known, that the Morin transition is grain size dependent first-order phase transition described by the following equation predicted by Amin et all.…”

Induction and control of room-temperature ferromagnetism in dilute Fe-doped SrTiO3 ceramics

“…It is worth mentioning that none of the above transition temperatures is close to Morin transition in Fe 2 O 3 at 260 K (Ref. 32) and the Verwey transition in Fe 3 O 4 at 120 K, 33 eliminating the presence of iron oxides as impurity phases with any significant contribution to the magnetism of our samples.…”

Nanocrystalline α-Fe2O3: A superparamagnetic material for w-LED application and waste water treatment

“…Many synthesis methods have been used to prepare Fe 2 O 3 nanoparticles [14][15][16][17][18]. A. Jahagirdar et al [2] synthesized dumbbell shaped α-Fe 2 O 3 nanoparticles by a low temperature combustion method and studied it's structural, magnetic and luminescence properties.…”