Structural and magnetic properties of self-assembled Sm–Co spherical aggregates

Saravanan, P.; Ramana, G. Venkata; Rao, K. Srinivasa; Sreedhar, B.; Vinod, V.T.P.; Chandrasekaran, V.

doi:10.1016/j.jmmm.2011.03.011

Cited by 19 publications

(13 citation statements)

References 24 publications

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“…Success in applying the chemical methods to synthesize FePt and ferrite nanoparticles inspired people to synthesize Sm-Co and Nd-Fe-B nanoparticles in similar approaches. A number of attempts have been made to synthesize the rare-earth containing hard magnetic nanoparticles with various chemical solution methods [108][109][110][111][112][113][114][115][116][117][118][119][120]. Chemical reduction and thermal decomposition of molecular precursors were also employed for the preparation of rare-earth transition-metal nanoparticles.…”

Section: Chemical Synthesis and Salt-matrix Annealingmentioning

confidence: 99%

Advances in nanostructured permanent magnets research

Poudyal¹,

Liu²

2012

J. Phys. D: Appl. Phys.

249

142

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This paper reviews recent developments in research in nanostructured permanent magnets (hard magnetic materials) with emphasis on bottom-up approaches to fabrication of hard/soft nanocomposite bulk magnets. Theoretical and experimental findings on the effects of soft phase and interface conditions on interphase exchange interactions are given. Synthesis techniques for hard magnetic nanoparticles, including chemical solution methods, surfactant-assisted ball milling and other physical deposition methods are reviewed. Processing and magnetic properties of warm compacted and plastically deformed bulk magnets with nanocrystalline morphology are discussed. Prospects of producing bulk anisotropic hard/soft nanocomposite magnets are presented.

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Section: Chemical Synthesis and Salt-matrix Annealingmentioning

confidence: 99%

Advances in nanostructured permanent magnets research

Poudyal¹,

Liu²

2012

J. Phys. D: Appl. Phys.

249

142

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“…Sm-Co nano- and micro- structures have been fabricated by various methods including ball-milling (Liu and McCormick, 1999 ; Zheng et al, 2012 ; Wang et al, 2013 ), co-precipitation (Zhang et al, 2011 ), sol-gel process (Suresh et al, 2012 ), and polyol process (Saravanan et al, 2011a ). However, these methods are difficult to control the dimension including diameter and length due to heterogeneous nucleation and growth.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Samarium-Cobalt Sub-micron Fibers and Their Excellent Hard Magnetic Properties

et al. 2018

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High-throughput synthesis of Samarium-Cobalt sub-micron fibers with controlled composition and dimension was demonstrated by combining electrospinning and reduction-diffusion processes. The composition of fibers was readily varied (8 < Sm < 20 at.%) by adjusting precursor composition whereas the diameter of fibers was precisely controlled by varying electrospinning parameters (e.g., applied voltage, solution feed rate, temperature, and humidity) to reach single-domain size. X-ray diffraction patterns confirmed that single phase Sm2Co17 fibers were synthesized when the metal precursor ratio (Sm3+/(Sm3++Co2+)) was precisely controlled at 10.6%, whereas mixed phases (i.e., Co-Sm2Co17 or Sm2Co17-Sm2Co7) were observed when the ratio is deviated from the stoichiometric. Magnetic saturation (Ms) of the synthesized fibers monotonically decreased with an increased in Sm content. In contrast, coercivity (Hci) monotonically increased with an increase in Sm content.

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“…The research on Sm-Co nanoparticles is, however, challenged by the requirement of high-temperature annealing above 800 C for alloy formation and crystalline ordering, which results in poor control of size, size-distribution, and phase purity. [5][6][7][8] SmCo 5 and Sm 2 Co 17 nanoparticles have previously been prepared by surfactant-assisted ball milling of bulk Sm-Co alloys, but these nanoparticles show a very low room-temperature coercivity of 100 Oe and a substantial reduction of magnetization due to the presence of surfactants, incomplete ordering, and oxidation. 5 In addition, ball milling process induces strains and amorphorization and also leads to the decomposition of the Sm-rich SmCo 5 phase.…”

mentioning

confidence: 99%

“…8 Low-temperature wet chemical polyol process at about 270 C using Co and Sm metal precursors in the presence of tetraethylene glycol resulted in SmCo 5 nanoparticles of particle sizes less than 20 nm with room temperature coercivities in the range of 100 to 1500 Oe. 6,7 Recently, the reduction of Sm(III) and Co(II) salts in tetraethylene glycol has been found to yield predominant Co 2 C phase with x-diffraction peaks similar to SmCo 5 .…”

mentioning

confidence: 99%

Magnetism of directly ordered Sm-Co clusters

Balamurugan

Skomski

et al. 2012

Journal of Applied Physics

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Sm-Co bulk alloys have shown superior permanent-magnet properties, but research on Sm-Co nanoparticles is challenging because of the need to control particle size, size-distribution, crystalline ordering, and phase purity. In the present study, a cluster-deposition method was used to produce Sm-Co nanoparticles having desired crystal structures without the requirement of subsequent high-temperature thermal annealing. Poorly crystallized SmCo5 nanoparticles exhibit a low room-temperature coercivity of only 100 Oe, whereas crystalline SmCo5 and Sm2Co17 nanoparticles show room-temperature coercivities of 2000 and 750 Oe, respectively. The direct synthesis of Sm-Co nanoparticles having sizes of less than 10 nm and a high degree of atomic ordering is an important step toward creating nanoparticle building blocks for permanent-magnets and other significant applications.

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Structural and magnetic properties of self-assembled Sm–Co spherical aggregates

Cited by 19 publications

References 24 publications

Advances in nanostructured permanent magnets research

Advances in nanostructured permanent magnets research

Synthesis of Samarium-Cobalt Sub-micron Fibers and Their Excellent Hard Magnetic Properties

Magnetism of directly ordered Sm-Co clusters

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