Single Domain SmCo5@Co Exchange-coupled Magnets Prepared from Core/shell Sm[Co(CN)6]·4H2O@GO Particles: A Novel Chemical Approach

Abstract

SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets.

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

“…8), is consistent with the above simple theoretical arguments. In some cases, two-stage loops, typical of spring-magnets, have also been observed [93][94][95]98,114,115,131,190,242,245,261,263,264,266,268,269,271,278,279,[282][283][284][285]289,294,295] (see Fig. 9).…”

“…9). As the thickness of a soft shell (conventional systems) or the diameter of a soft core (inverse systems) becomes very large the loop is no longer smooth and a constriction at low fields [93,114,115,190,245,261] is observed implying the formation of a pseudo-domain wall in the soft counterpart. However, several systems exhibit constricted loops even for rather small soft volumes.…”

“…First, it should be pointed out that given that we are dealing with nanoparticles the core and shell sizes are rather small (i.e., usually smaller than 2 H ), thus, most of the systems exhibit smooth hysteresis loops typical of strongly exchange coupled hard-soft counterparts. For conventional systems, i.e., when starting from a hard core, most systems report enhanced overall M S and reduced H C as soft layers are grown, [93,103,110,111,114,125,[127][128][129][130]132,136,140,190,[242][243][244][245][246]248,263,271,275,276,286,288,289] as expected from the dependence of H N on the amount of soft phase (see Fig. 7).…”

Well protected SmCo nanoclusters: fabrication and transformation to single crystals

“…Crystalline structure promotes anisotropy of the nanostructured SmCo as compared to the corresponding amorphous structure because of magnetocrystalline anisotropy. Various chemical 7,8 and physical 3,[9][10][11][12] methods were employed for the synthesis of crystallized SmCo NPs. Chemical methods, have limitations to control size and purity simultaneously.…”

Magnetic-Plasmonic Heterodimer Nanoparticles: Designing Contemporarily Features for Emerging Biomedical Diagnosis and Treatments

“…Specific characteristics of rod-shape structures are a possible reason to outperform spherical particles. For instance, the shape anisotropy remarkably affected hyperthermia efficiency [160,161,162]. In 2007, Wetz et al pioneered rod-shape heterodimers by synthesizing Co-Au structures via nucleation control of Au upon Co seeds [80].…”