Magnetic Clusters in Molecular Beams, Metals, and Semiconductors

Abstract

The evolution of magnetic order from the microscopic to the macroscopic regime may be studied with the use of nanometer-scale clusters. A variety of new techniques can be employed to control the size of the magnetic clusters from the atomic level. Molecular beams are used to construct and measure the magnetic properties of isolated metallic clusters. Superparamagnetic metallic particles embedded in a metal exhibit dramatic field-dependent changes in electrical conduction, providing a measure of spin-dependent scattering. Related efforts in semiconductor hosts with the use of ion implantation have generated room-temperature ferromagnetic clusters that can be directly imaged by magnetic force microscopy.

Size dependence of nanostructures: Impact of bond order deficiency

“…Magnetic nanocomposites also manifest enhanced or tailored magnetic properties under various conditions [49]. At low temperatures, the saturation magnetization (M S ) of a small solid is higher than that of the bulk with oscillation features when the solid size is reduced; however, at the ambient temperatures, an opposite trend dominates.…”

3D Monolayers of 1,4-Benzenedimethanethiol on Au and Ag Clusters: Distinct Difference in Adsorption Geometry with the Corresponding 2D Monolayers

“…A range of cluster sizes can also be prepared by appropriate manipulation of the kinetic parameters (4). Apart from the properties of the metal core, the molecular chemistry of monolayers has also attracted attention (5). The diversity of the chemistry of self-assembled monolayers (SAMs) (6) grown on planar surfaces (2D SAMs) can be directly adapted to monolayers on cluster surfaces (3D SAMs) (7).…”

Microwave ferrites, part 1: fundamental properties

“…28 Grown cobalt ferrite films were single phase polycrystalline spinel structure without any Most significant properties of magnetic ceramic materials, namely magnetic saturation, coercivity, magnetization, and loss change drastically when dimensions are reduced to nanoscale. 178,179 Reduction in size of the magnetic material leads to novel properties as compared to the bulk material due to small volume and high surface/volume ratio, and nanoscale magnetic materials are suggested for possible consideration in applications such as high-density recording, 180 color imaging, 181 ferrofluids, 181,182 and magnetic refrigerators. 178,179 Typical lexicon for size reduction is that it leads to novel properties as compared to the bulk material due to the small volume and the high surface/volume ratio if the surface effects can be dealt with successfully.…”

“…178,179 Reduction in size of the magnetic material leads to novel properties as compared to the bulk material due to small volume and high surface/volume ratio, and nanoscale magnetic materials are suggested for possible consideration in applications such as high-density recording, 180 color imaging, 181 ferrofluids, 181,182 and magnetic refrigerators. 178,179 Typical lexicon for size reduction is that it leads to novel properties as compared to the bulk material due to the small volume and the high surface/volume ratio if the surface effects can be dealt with successfully. For example, when the size of the magnetic particle is smaller than the critical size for multi-domain formation, the particle exists in a single-domain, where the domain-wall resonance is avoided, and therefore, the material could be use at higher frequencies.…”