Direct evidence for size-dependent chemical and magnetic ordering in L10-FePt nanoparticles is obtained by measuring monodisperse prepared the "salt-matrix annealing" technique. Quantitative correlations show that long-range chemical-ordering parameter, Curie temperature (see figure), saturated magnetization drop significantly with decreasing particle size.

Monodisperse spherical FeCo nanoparticles were synthesized by reduction decomposition of Fe(acac)3 and Co(acac)2 in the presence surfactants 1,2-hexadecanediol. The particle size can be controlled varying surfactants. on surface nanocrystal protects them from oxidation. saturation magnetization as-synthesized particles is found to dependent. made air-stable annealing at 500 °C for 30 min without causing sintering.

Hard magnetic nanoparticles based on the Sm(2)Co(17) and SmCo(5) systems have been successfully produced using a surfactant-assisted ball milling technique. A size-selection process has developed to obtain of different sizes with narrow size distribution. Significant room-temperature coercivity up 3.1 kOe achieved Sm(2)Co(17)-based an average 23 nm. It found that surfactants play multifold roles in processing.

A simple method to produce ferromagnetic FePt nanoparticle dispersions by thermal annealing of core/shell-structured FePt/MgO nanoparticles and removal MgO in the presence hexadecanethiol oleic acid is reported. The have a room temperature coercivity 1 T magnetization 56.4 emu per gram FePt, are suitable for single-particle magnetism studies other magnetic applications.

SmCo5 magnets are synthesized by the facile Ca reduction of core/shell-structured Co/Sm2O3 nanoparticles, as schematically illustrated in figure. The exhibit coercivities reaching 24 kOe at 100 K and 8 room temperature. synthesis represents an important first step towards fabrication SmCo-based exchange-spring nanocomposites for high-performance permanent magnet applications.

This paper reports an improved synthesis of hard magnetic fct-FePt nanoparticles (NPs) from reductive annealing fcc-FePt/Fe3O4/MgO NPs followed by MgO removal. The fcc-FePt/Fe3O4 are made a one-pot reaction Pt(acac)2 with Fe(CO)5 in the presence oleic acid and oleylamine coated layer via thermal decomposition Mg(acac)2. coating prevents FePt sintering under high temperature conditions. obtained 650 °C show coercivity value 2 T at 300 K, suitable for various nanomagnetic applications.

We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic α-Fe phase particles homogeneously in hard SmCo through severe plastic deformation. The soft-phase particle size reduced from micrometers to smaller than 15 nm upon Up 30% of incorporated into composites without coarsening. A warm compaction process plastically deformed powder then produces bulk magnets fully dense nanocomposites with energy product up 19.2 MGOe owing...

In a real magnet, the relation between isothermal remanence Jr(H) and dc demagnetization Jd(H) is expressed as δm(H)=[Jd(H)−Jr(∞)+2Jr(H)]/J(∞). It believed that nonzero δm due to interactions particles in magnet. Using Pr2Fe14B sample, examined by micromagnetic finite element method. The positive value of primarily caused intergrain exchange coupling. decrease coupling results drop maximum δm. However, variation anisotropy grain boundaries produces no change A Henkel plot suggested be...

Hard magnetic nanocomposites SmCo5∕Fex (x=0–2.9) are synthesized by a simultaneous calcium reduction of Sm–Co–O and Fe3O4 nanoparticles. The composites consist nanostructured SmCo5 Fe with their average grain sizes at 29 8nm, respectively. properties the can be tuned controlling composition. SmCo5∕Fe1.5 shows an enhanced remanent magnetization 56emu∕g (45emu∕g for SmCo5). largest coercivity value 11.6kOe is achieved SmCo5∕Fe0.23. synthesis represents general process toward SmCo-based...

We report a facile synthesis of ferromagnetic SmCo nanoparticles (NPs) via controlled reduction SmCo–O NPs. The NPs were prepared by co-precipitation Co(II) and Sm(III) acetates with hexadecyl-trimethylammonium hydroxide embedded in CaO matrix. 7 nm SmCo3.6–O reduced Ca at 960 °C converted into 6 SmCo5 their coercivities reaching 7.2 kOe. provides viable route to compositions magnetism for high performance permanent magnetic applications.

The push to decarbonize has spurred the demand for clean energy technologies such as electric vehicles (EVs) and wind turbines (WTs). These rely on rare earth permanent magnets (REPMs), namely Neodymium-Iron-Boron (NdFeB) that in turn elements (REEs), including Neodymium (Nd), Dysprosium (Dy). As increases, so will Nd Dy-containing REPMs. Both Dy are critical prone supply chain risks. our reliance them it becomes essential anticipate future market dynamics these elements. This paper aims...

Nd–Fe–B nanoparticles have been obtained by using surfactant-assisted ball milling and subsequent size-selection technique. Structural analyses show that with two particle sizes around 10 100nm were obtained. The partially amorphous give their room-temperature coercivities 0.1 1.5kOe for the small large nanoparticles, respectively. As temperature decreases to 200K, coercive force of increases 50% due enhancement magnetocrystalline anisotropy Nd2Fe14B phase in particles.

We report here the preparation of Fe, Co, and FeCo nanoplates nanoparticles by ball milling in presence surfactants organic solvents. By controlling centrifugation conditions, with different sizes were successfully obtained, from slurries top part solutions, respectively. The thickness is range 20–200 nm their diameter 5 to 30 μm. about 6 show superparamagnetic behavior at room temperature are ferromagnetic low temperatures blocking 33, 103, 54 K, It found that play multifold roles process.

The melt-spinning technique offers an opportunity for tailoring magnetic properties by controlling the structures and microstructures in both single-phase composite magnets. This review first broadly discusses principle of cooling control, amorphization, crystallization, annealing, consolidation melt-spun ribbons. phase, microstructure, popular nanocrystalline magnets are reviewed, followed nanocomposite consisting magnetically hard soft phases. precipitation-hardened materials prepared melt...

High density bulk FePt/Fe3Pt nanocomposite magnets have been prepared by high-pressure warm compaction of chemically synthesized FePt and Fe3O4 nanoparticles. It is found that the increases with pressure temperature. Density samples up to 95% theoretical value has obtained while nanostructured morphology retained. also observed a high expedites phase transition from disordered face-centered-cubic structure L10 structure, leading temperature in compacts one hundred degrees lower than usual....

Bimagnetic FePt/Fe3O4 nanoparticles with core/shell or heterodimer structure have been prepared using a sequential synthetic method. The dimension of both FePt and Fe3O4 was tuned by varying the synthesis parameters. as-synthesized bimagnetic were superparamagnetic at room temperature. After being annealed in reducing atmosphere, converted to hard magnetic nanocomposite enhanced energy products due exchange coupling between soft phases. It found that nanocomposites made from is stronger than...

The SmCox (x=3.5, 4, 5, 6, 8.5, and 10) magnetic nanoparticles with different composition have been prepared by surfactant-assisted ball milling technique. By controlling the settle-down time centrifugation conditions, particle size narrow distribution were successfully obtained. It was observed that SmCo become unstable increasing Sm content. also coercivity of increases Co content size, indicating a complex effect on hardening hard nanoparticles.

Anisotropic bonded magnets are fabricated by surfactant-assisted ball milling in a magnetic field and alignment of the milled chip-like nanoparticles Sm–Co Nd–Fe–B materials. It is found that application fields during strengthens anisotropy chips therefore improves alignment. For SmCo 5 phase-based chips, for instance, energy products up to 26.0 MG Oe 19.1 obtained magnets, respectively. This combined technique opens new approach fabrication anisotropic various applications.

Rare earth elements (REEs) such as Neodymium (Nd) and Dysprosium (Dy) are used in Earth Permanent Magnets (REPMs). Neodymium-iron-boron (NdFeB) magnets offer the strongest magnetic field per volume among all available market, which enables lightweight compact product designs. NdFeB have thus become indispensable emerging clean technologies wind turbines electric vehicles (EVs). Global demand for these renewables is increasing due to environmental considerations, energy security, consumer...