Surface effects in metallic iron nanoparticles

Abstract

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Enhancement of the magnetic anisotropy of nanometer-sized Co clusters: Influence of the surface and of interparticle interactions

“…Our experimental results indicate then that there exists a rather large contribution of the surface of the particles to the net anisotropy. The enhancement of the magnetic anisotropy of nanometer sized metallic particles with respect to the bulk has been previously reported by several authors 8,9,24 . For Co particles with diameters varying between 4.4 and 1.8 nm, Chen and coworkers 9 obtained K ef f which increases from about 5 × 10 6 erg/cm 3 to about 3 × 10 7 erg/cm 3 .…”

“…In addition, the net anisotropy of the particle exceeds the bulk value. 8,9 This excess was recently correlated to the augmentation of the orbital magnetic moment of the peripheral atoms. 10,11 Magnetic nanoparticles are also good candidates for the study of quantum effects in intermediate scales between the microscopic and the macroscopic classical world.…”

Decreasing nanofluid droplet heating time with alternating magnetic fields

“…16,17 It is important to point out that V is the nanoparticle volume without the coating layer ͑V ϵ D 3 / 6͒, and K is the magnetic anisotropy, which is strongly dependent upon the material, shape and also particle size. 18,19 The process of heat generation in magnetic nanofluids under the influence of a magnetic field is due to in part by the mobility of the nanoparticles inside the fluid and in part by heat conduction from the nanoparticle to the liquid carrier. Figure 1 shows a schematic representation of a nanofluid droplet under alternating magnetic field during one cycle.…”

Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

“…37 It has been reported that the values of K 1 depend on interface 49 or finite size of the magnetic system. 50 In case of magnetic nanoparticles, surface anisotropy contributes to the overall anisotropy of particles, which arises due to the lower coordination and broken symmetry at surface. 51,52 Rusponi et al 53 reported that the atoms residing at the edge of the two dimensional cobalt islands contribute significantly to the anisotropy.…”