Experimental studies of neodymium ferrites doped with three different transition metals

Chemical synthesis and magnetic properties of monodisperse cobalt ferrite nanoparticles

“…The NPs is only 315 Oe at 300 K due to the additional thermal activation energy which decreasing the exchange interaction between spin moment. At 10 K, the coercivity values are in the same order of magnitude as those of CoFe2O4 nanotubes [14] and nanowires [26] fabricated by electrospinning, nanorods synthesized by microemulsion [27] and nanoparticles synthesized by co-precipitation method [28]. Finally, the values of saturation magnetization, Ms, obtained for CoFe2O4 NPs in this work, are in the range of 58 to 65 emu/g.…”

Influence of neodymium substitution on structural, magnetic and spectroscopic properties of Ni–Zn–Al nano-ferrites

“…Moreover, the decrease in saturation magnetization of our ferrite samples can be explained on the basis of magnetic moment of metal ions in the samples. Magnetic moment of Nd 3+ ion (3 μ B ) 57 is smaller than that of Fe 3+ ion (5 μ B ), 58 when Fe 3+ ions in nanoparticles spinel Ni 0.6 Zn 0.4 Al 0.5 Fe 1.5 O 4 are partially doped by Nd 3+ ions, the Nd 3+ ions are preferentially occupied the octahedral sites (B-sites), which leads to the decrease in the net magnetic moment of octahedral sites in Ni 0.6 Zn 0.4 Al 0.5 Fe 1.5− x Nd x O 4 with the rise of x . Similar saturation magnetization behavior has been reported for many rare earth doped spinel ferrites.…”

Evolution of the Magnetic and Structural Properties with the Chemical Composition in Oleate-Capped MnxCo1–xFe2O4 Nanoparticles

“…crystallize in the spinel structure, which is described by a unit cell of 32 cubic close-packed oxide anions in which the metal cations occupy 8 tetrahedral ( T d -site) and 16 octahedral sites ( O h -site). , The stoichiometry, the nature of the divalent cations, and their distribution among these two types of interstitial sites (usually summed up by the so-called “inversion degree”) are key features to modulate the magnetic properties (e.g., saturation magnetization and anisotropy) of the cubic ferrite, beyond size and shape changes. − Among these materials, cobalt ferrite (CoFe 2 O 4 ) features the highest anisotropy constant (2.9 × 10 5 J m –3 ), which makes it the sole magnetically hard phase, but for some applications, the higher toxicity of cobalt ions in comparison with others has to be taken into account. Besides the size-, − shape-, ,− and coating-tuning − approaches, cation substitution (also improperly called doping) is a well-known strategy to modulate the properties of nanostructured spinels. − The co-presence of different types of divalent cations in the structure (i.e., the production of chemically mixed ferrites) represents a successful strategy to finely tune the magnetic behavior and reduce the toxicity of the final product. , …”