Synthesis of L10 alloy nanoparticles. Potential and versatility of the pre-ordered Precursor Reduction strategy

Varvaro, G.; Imperatori, P.; Laureti, S.; Cannas, Carla; Ardu, Andrea; Plescia, P.; Capobianchi, A.

doi:10.1016/j.jallcom.2020.156156

Cited by 13 publications

(29 citation statements)

References 78 publications

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“…Ferromagnetic (FM)/heavy metal (HM) multilayers (MLs), such as [X/Pt] N and [X/Pd] N (X = Co, Fe; N : bilayer repetition) thin film stacks, have been extensively studied for many years owing to their strong perpendicular magnetic anisotropy (PMA) arising at the interface between the layers (10 5 –10 6 J/m 3 ), − which makes them of great interest for different technological applications. − [Co/Pt(Pd)] N multilayers were first proposed as perpendicular recording media in high density storage technology as a valid alternative to CoPt or FePt chemically ordered alloys. − To this purpose, a wide number of studies have been carried out aimed at disclosing the relationship between the PMA and the ML structural features, i.e., thickness of the sub-layers, repetition number N , or the crystallographic orientation. , The large tunability of their physical properties has been then exploited in spintronic devices, such as giant magnetoresistive (GMR) spin valves and magnetic tunneling junctions (MTJs), where [Co/Pt(Pd)] N multilayers have been used as both the free and the reference electrodes. For this purpose, different architectures have been proposed, with the ML used as a single FM electrode or in combination with suitable non-magnetic spacers (e.g., Ru, Ir, Cu, etc.)…”

Section: Introductionmentioning

confidence: 99%

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Verna

Alippi

Offi

et al. 2022

ACS Appl. Mater. Interfaces

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Nowadays, a wide number of applications based on magnetic materials rely on the properties arising at the interface between different layers in complex heterostructures engineered at the nanoscale. In ferromagnetic/heavy metal multilayers, such as the [Co/Pt] N and [Co/Pd] N systems, the magnetic proximity effect was demonstrated to be asymmetric, thus inducing a magnetic moment on the Pt (Pd) layer that is typically higher at the top Co/Pt(Pd) interface. In this work, advanced spectroscopic and imaging techniques were combined with theoretical approaches to clarify the origin of this asymmetry both in Co/Pt trilayers and, for the first time, in multilayer systems that are more relevant for practical applications. The different magnetic moment induced at the Co/Pt interfaces was correlated to the microstructural features that are in turn affected by the growth processes that induce a different intermixing during the film deposition, thus influencing the interface magnetic profile.

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Section: Introductionmentioning

confidence: 99%

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Verna

Alippi

Offi

et al. 2022

ACS Appl. Mater. Interfaces

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“…Figure 1b displays XRD patterns of CoPt nanoparticles (NPs), rGO/CoPt, and rGO/CoPt/Ag nanocomposites. The broad peak at 2θ = 41.85 • corresponds to the plane of the face-centered tetragonal (FCT) CoPt (111) [30]. Figure 1b displays that the rGO/CoPt peak at 2θ = 41.86 • indicates the presence of CoPt NPs, confirming the formation of the rGO/CoPt nanocomposite.…”

Section: Characterization and Properties Of Copt Go Rgo Rgo/copt And Rgo/copt/agmentioning

confidence: 78%

Preparation of Reduced-Graphene-Oxide-Supported CoPt and Ag Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

et al. 2021

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Composite nanostructure materials are widely used in catalysis. They exhibit several characteristics, such as the unique structural advantage and the synergism among their components, which significantly enhances their catalytic performance. In this work, CoPt nanoparticles and reduced-graphene-oxide-based nanocomposite catalysts (rGO/CoPt, rGO/CoPt/Ag) were prepared by using a facile co-reduction strategy. The crystalline structure, morphology, composition, and optical characteristics of the CoPt nanoparticles, rGO/CoPt nanocomposite, and rGO/CoPt/Ag nanocomposite catalysts were investigated by a set of techniques. The ID/IG value of the rGO/CoPt/Ag nanocomposite is 1.158, higher than that of rGO/CoPt (1.042). The kinetic apparent rate constant, k, of the rGO/CoPt/Ag nanocomposite against 4-nitrophenol (4-NP) reduction is 5.306 min−1, which is higher than that of CoPt (0.495 min−1) and rGO/CoPt (1.283 min−1). The normalized rate constant, knor, of the rGO/CoPt/Ag nanocomposite is 56.76 min−1mg−1, which is higher than some other catalytic materials. The rGO/CoPt/Ag nanocomposite shows a significantly enhanced catalytic performance when compared to CoPt nanoparticles and the rGO/CoPt nanocomposite, which may confirm that the novel rGO/CoPt/Ag nanocomposite is a promising catalyst for the application of catalytic fields.

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“…The formation of L1 0 FeNi necessitates a very high rate of interdiffusion of Fe and Ni in the FeNi lattice below 593 K (temperature for the order to disorder transformation). In order to induce high rate of diffusion at low temperatures and to achieve the formation of L1 0 FeNi, several processing techniques such as high energy neutron , or electron or ion beam irradiation, severe plastic deformation, − mechanical alloying, , and approaches such as crystallization from amorphous FeNiSiPBCu, , field-assisted heat treatment of FeNi , and chemically induced ordering such as nitrogen insertion and topotactic extraction, pre-ordered precursor reduction, and so forth are studied.…”

Section: Introductionmentioning

confidence: 99%

Formation of L1₀ Ordering in FeNi by Mechanical Alloying and Field-Assisted Heat Treatment: Synchrotron XRD Studies

et al. 2023

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L10-ordered FeNi, tetrataenite, found naturally in meteorites is a predilection for next-generation rare-earth free permanent magnetic materials. However, the synthesis of this phase remains unattainable in an industrially relevant time frame due to the sluggish diffusion of Fe and Ni near the order–disorder temperature (593 K) of L10 FeNi. The present work describes the synthesis of ordered L10 FeNi from elemental Fe and Ni powders by mechanical alloying up to 12 h and subsequent heat treatment at 623 K for 1000 h without a magnetic field and for 4 h in the presence of 1.5 T magnetic field. Also, to address the ambiguity of L10 phase identification caused by the low difference in the X-ray scattering factor of Fe and Ni, synchrotron-based X-ray diffraction is employed, which reveals that 6 h milling is sufficient to induce L10 FeNi formation. Further milling for 12 h is done to achieve a chemically homogeneous powder. The phase fraction of L10-ordered FeNi is quantified to ∼9 wt % for 12 h milled FeNi, which increases to ∼15 wt % after heat treatment. Heat treatment of the milled powder in a magnetic field increases the long-range order parameter (S) from 0.18 to 0.30. Further, the study of magnetic properties reveals a decrease in magnetic saturation and a slight increase in coercivity with the increase in milling duration. At the same time, heat treatment in the magnetic field shows a considerable increase in coercivity.

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Synthesis of L10 alloy nanoparticles. Potential and versatility of the pre-ordered Precursor Reduction strategy

Cited by 13 publications

References 78 publications

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Preparation of Reduced-Graphene-Oxide-Supported CoPt and Ag Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

Formation of L1₀ Ordering in FeNi by Mechanical Alloying and Field-Assisted Heat Treatment: Synchrotron XRD Studies

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Synthesis of L10 alloy nanoparticles. Potential and versatility of the pre-ordered Precursor Reduction strategy

Cited by 13 publications

References 78 publications

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Disclosing the Nature of Asymmetric Interface Magnetism in Co/Pt Multilayers

Preparation of Reduced-Graphene-Oxide-Supported CoPt and Ag Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

Formation of L10 Ordering in FeNi by Mechanical Alloying and Field-Assisted Heat Treatment: Synchrotron XRD Studies

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Formation of L1₀ Ordering in FeNi by Mechanical Alloying and Field-Assisted Heat Treatment: Synchrotron XRD Studies