Magnetic Study of the Fe Coated by Au Nanoparticles

Abstract

Nanosized iron-gold magnetic nanoparticles with an average particle size 10 nm were prepared by a reverse micelle method. The magnetic properties measurements of DC and AC magnetization confirm behaviour typical of a superparamagnetic system, such as the irreversibility of the zero-field-cooled and field-cooled curves, the frequency dependence of a blocking temperature T B , and revealing of coercivity H C below blocking temperature. The quantitative analysis of AC susceptibility due to value of parameter C 1 = ∆T B /(T B ∆ log f ) = 0.0242 confirming the existence of inter-particle interaction in our system.

Influence of Surface Effects on Magnetic Behavior of Hematite Nanoparticles Embedded in Porous Silica Matrix

“…The fine hematite particles (α-Fe 2 O 3 ) are known to be antiferromagnetic under the Morin transition T M , and the antiferromagnetic order is frustrated at the surface . Therefore, the antiferromagnetic hematite nanoparticles (on the contrary to the bulk hematite) could exhibit superparamagnetic relaxation of their spin lattices as well as permanent magnetic moments arising from uncompensated surface spins.…”

“…However, some portion of the nanoparticles are trapped on the external surface of PNS. In our recent work, we have shown that the magnetic behavior of such systems is governed by two contributions: ferromagnetic and paramagnetic, which come from the nanoparticles incorporated inside the pores and those trapped on the external surface, respectively …”

Iron-containing nanomaterials: synthesis, properties, and environmental applications

“…The magnetic properties measurements confirmed behavior typical of a superparamagnetic system. 81,82 The XPS studies of the core-shell Fe/Au Nps indicate that besides Fe 0 inside the cores, small amounts of Fe(II,III), located onto the gold surface, were also formed during the sample preparation. A certain number of reports have mentioned pure iron core, for instance Fe core/Au shell (11 nm Fe core, 2.5 nm Au shell) without iron oxides.…”

State of the Art of the Bi- and Trimetallic Nanoparticles on the Basis of Gold and Iron

“…For instance, nanosized iron-gold magnetic nanoparticles with an average particle size 5-25 nm were prepared by a reverse micelle method, which is the principal technique in obtaining core-shell Nps. The magnetic properties measurements confirmed behavior typical of a superparamagnetic system [24,25]. The XPS studies of the core-shell Fe/Au nanoparticles indicated that besides Fe 0 inside the cores, small amounts of Fe (II, III), located onto the gold surface, were also formed during the samples preparation.…”