Synthesis and Magnetic Properties of CoPt Nanoparticles

Trung, Truong Thanh; Nhung, Do Thi; Nam, Nguyễn Hoàng; Luong, Nguyen Hoang

doi:10.1007/s11664-016-4562-x

Cited by 10 publications

(5 citation statements)

References 13 publications

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“…Upon annealing at T = 300 • C, the intensity of the Co-Ir hcp (002) peak increases, indicating the introduction of additional thermal-induced CoIr alloying. Importantly, we observed the emergence of fundamental Co-Pt fcc (111) peak at ∼40.8 • across both metallic multilayers [20,36,40], evidently a result of the inward diffusion of Pt into the CoB layer (figures 5(a) and (b)). The Co-Pt peak indicates the likely formation of CoPt 3 binary alloy, wherein a Co-Pt fcc (111) peak position of 40.5 • has been reported for Pt content up to 70% [20].…”

Section: Thermal Annealing Effectsmentioning

confidence: 75%

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Intermixing induced anisotropy variations in CoB-based chiral multilayer films

Tan¹,

Lim²,

Seng³

et al. 2021

J. Phys. D: Appl. Phys.

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We examine the atomic intermixing phenomenon in three distinct amorphous CoB-based multilayer thin film platforms — Pt/CoB/Ir, Ir/CoB/Pt and Pt/CoB/MgO — which are shown to stabilise room-temperature chiral magnetic textures. Intermixing occurs predominantly between adjacent metallic layers. Notably, it is stack-order dependent, and particularly extensive when Ir sits atop CoB. Intermixing induced variations in magnetic properties are ascribed to the formation of magnetic dead layer arising from CoIr alloying in the metallic stacks. It also produces systematic variations in saturation magnetization, by as much as 30%, across stacks. Crucially, the resulting crossover CoB thickness for the transition from perpendicular to in-plane magnetic anisotropy differs by more than 2 across the stacks. Finally, with thermal annealing treatment over moderate temperatures of 150–300 °C, the magnetic anisotropy increases monotonically across all stacks, coupled with discernibly larger H c for the metallic stacks. These are attributed to thermally induced CoPt alloying and MgO crystallization in the metallic and oxide stacks, respectively. Remarkably, the CoB in the Pt/CoB/MgO stacks retains its amorphous nature after annealing. Our results set the stage for harnessing the collective attributes of amorphous CoB-based material platforms and associated annealing processes for modulating magnetic interactions, enabling the tuning of chiral magnetic texture properties in ambient conditions.

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Section: Thermal Annealing Effectsmentioning

confidence: 75%

“…Thermal annealing of multilayer stacks brings about considerable changes to the interfacial roughness, interlayer atomic diffusion, crystallization, phase transitions, hence altering their magnetic and transport properties [20,23,36,[40][41][42]. Moderate annealing, e.g.…”

Section: Thermal Annealing Effectsmentioning

confidence: 99%

Intermixing induced anisotropy variations in CoB-based chiral multilayer films

Tan¹,

Lim²,

Seng³

et al. 2021

J. Phys. D: Appl. Phys.

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“…We investigated the crystalline symmetry as the Fm3 " (JCPDS: 15-0806) space groups of fcc-Co cubic phases for both samples from the simulation [24]. The lattice constants were found to be 3.86 Å and 3.88 Å for the samples prepared under Ar pressure and air, respectively [25]. The d(111) spacing is calculated via Rietveld refinement and found to be 2.23 Å and 2.24 Å for CP-Ar and CP-Air NPs, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…86 Å and 3.88 Å for the samples prepared under Ar pressure and air, respectively[25]. The d(111) spacing is calculated via Rietveld refinement and found to be 2.23 Å and 2.24 Å for CP-Ar and CP-Air NPs, respectively.…”

mentioning

confidence: 96%

Comparing Different Approaches to Form Cobalt Oxide Layer on CoPt Nanoparticles

Kaya

Adanur

Akyol

et al. 2020

Adıyaman University Journal of Science

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We have studied the effect of preparation methods, under argon gas and in the air environment, on the cobalt oxide formation of CoPt nanoparticles by the polyol process. The formation of cobalt oxide for both samples was investigated by the x-ray diffraction (XRD) method and cobalt oxide peaks are observed in the air prepared sample. Rietveld refinement analyses revealed that all samples exhibit a chemically distorted cubic crystal structure. The average particle size was determined <8 nm by scanning electron microscopy (SEM) and energydispersive x-ray spectroscopy (EDS) was revealed the chemical compositions with possible oxygen formation in the structure. The blocking temperature is reduced to 28 K in the air prepared sample due to cobalt oxide formation. The hysteresis gap disappeared above the blocking temperature and no saturation is observed up to ±5 T external field due to the system switching

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“…Nanoparticles are intensively studied for optical [1][2][3][4], catalytic [5][6][7], magnetic [8][9][10][11][12] and storage applications [13][14][15][16][17][18]. FePt nanoparticles are interesting candidates for ultra-high density storage applications due to their extremely high magnetocrystalline anisotropy when chemically ordered in the L1 0 phase [19,20].…”

mentioning

confidence: 99%

Elaboration of Nanomagnet Arrays: Organization and Magnetic Properties of Mass-Selected FePt Nanoparticles Deposited on Epitaxially Grown Graphene on Ir(111)

et al. 2019

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The moiré pattern created by the epitaxy of a graphene sheet on an iridium substrate can be used as a template for the growth of 2D atomic or cluster arrays. We observed for the first time a coherent organization of hard magnetic preformed FePt nanoparticles on the 2D lattice of graphene/Ir(111). Nanoparticles of 2 nm diameter have been mass-selected in gas phase and deposited with a low energy on the hexagonal moiré pattern. Their morphology and organization have been investigated using Grazing Incidence Small Angle X-ray Scattering, while their magnetic properties have been studied by X-ray Magnetic Circular Dichroism, both pointing to a FePt cluster/graphene surface specific interaction. The spatial coherence of the nanoparticles is preserved upon annealing up to 700°C where the hard magnetic phase of FePt is obtained.

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Synthesis and Magnetic Properties of CoPt Nanoparticles

Cited by 10 publications

References 13 publications

Intermixing induced anisotropy variations in CoB-based chiral multilayer films

Intermixing induced anisotropy variations in CoB-based chiral multilayer films

Comparing Different Approaches to Form Cobalt Oxide Layer on CoPt Nanoparticles

Elaboration of Nanomagnet Arrays: Organization and Magnetic Properties of Mass-Selected FePt Nanoparticles Deposited on Epitaxially Grown Graphene on Ir(111)

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