Characteristics of cobalt adsorbed iron oxide tapes

Reversible post-synthesis tuning of the superparamagnetic blocking temperature of γ-Fe2O3nanoparticles by adsorption and desorption of Co(ii) ions

“…12 In this context, the improvement of the coercivity, H C , of acicular, sub-micron sized, c-Fe 2 O 3 particles for their application in recording media has been extensively studied since the 1960s. [13][14][15] This enhancement has been achieved by (i) adsorbing Co(II) ions on the surface of the particles, (ii) growing an epitaxial layer of CoFe 2 O 4 , or (iii) body-doping c-Fe 2 O 3 particles. 16 Despite the number of publications dealing with such improvement of the magnetic properties of acicular submicron particles, very little work has been carried out on smaller, i.e., few nanometers, sized particles.…”

Matériaux pour l'enregistrement magnétique haute densité

“…Passée cette valeur, le cobalt se retrouve sous la forme d'hydroxyde non magnétique et la coercivité décroît. Les coercivités optimales atteintes sont de 200 à 300 Oe supérieures à celles des précurseurs [21].…”

Room-temperature-persistent magnetic interaction between coordination complexes and nanoparticles in maghemite-based nanohybrids

“…[35][36][37][38][39] Ligand exchange has been a well-developed surface functionalisation strategy, [40][41][42][43][44][45] so is metal ion chemisorption, and especially Co(II) ions, which have been widely used to functionalise maghemite. 30,34,[46][47][48][49][50][51][52][53][54] In the case of Co(II) ions however, synthetic strategies focused on and resulted in aggregated, sometimes doped, samples. This led us to explore an alternative surface functionalisation approach with a special emphasis on the use of soft aqueous conditions and the preparation of stable colloidal assemblies.…”