Magneto-orientational properties of ionically stabilized aqueous dispersions of Ni(OH)2 nanoplatelets

Meyer, Michaël; Raǐkher, Yu. L.; Sandre, Olivier; Bée, Agnès; Cabuil, Valérie; Dupuis, Vincent; Licinio, Júlio; Perzynski, R.

doi:10.1140/epje/i2007-10338-5

Cited by 3 publications

(3 citation statements)

References 28 publications

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“…The observation of a nematic phase in suspensions of nanoparticles of a rather low aspect ratio, D/t ∼ 6, is actually remarkable. Indeed, nematic phases were so far mostly reported for much more anisotropic particles of aspect ratios ranging from ∼12 for gibbsite and Ni(OH) 2 platelets 25 to ∼1000 for clay, niobates, and graphene nanosheets. 26−29 Nevertheless, numerical simulations of hard discs predict that both the nematic and columnar phases can be stable for aspect ratios as low as ∼6 and ∼4, respectively, albeit at very large concentrations.…”

Section: ■ Results and Discussionsupporting

confidence: 88%

“…However, it remains smaller than the huge value (0.55 T –2 ) obtained for suspensions of uncompensated antiferromagnetic α-FeOOH nanorods . A similar effect was studied by X-ray scattering on colloidal dispersions of Ni(OH) 2 nanoplatelets …”

Section: Resultssupporting

confidence: 66%

“…37 A similar effect was studied by X-ray scattering on colloidal dispersions of Ni(OH) 2 nanoplatelets. 25 The same kind of experiments was made by applying a highfrequency ac electric field to the isotropic part of the 30 wt % colloidal suspension of CeF 3 nanodiscs. The sample also turned birefringent as a result of the alignment of the particles in the electric field.…”

Section: ■ Results and Discussionmentioning

confidence: 77%

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Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs

et al. 2019

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The design of high-performance energy-converting materials is an essential step for the development of sensors but the elaboration of the bulk materials currently used remains costly and difficult. Therefore, a different approach based on the self-assembly of nanoparticles has been explored. We report on the preparation by solvothermal synthesis of highly crystalline CeF 3 nanodiscs. Their surface modification by bisphosphonate ligands led to stable, highly concentrated, colloidal suspensions in water. Despite the low aspect ratio of the nanodiscs (~ 6), a liquid-crystalline nematic phase spontaneously appeared in these colloidal suspensions. Thanks to the paramagnetic character of the nanodiscs, the nematic phase was easily aligned by a weak (0.5 T) magnetic field, which provides a simple and convenient way of orienting all the nanodiscs in suspension in the same direction. Moreover, the more dilute, isotropic, suspensions displayed strong (electric and magnetic) field-induced orientation of the nanodiscs (Kerr and Cotton-Mouton effects), with fast enough response times to make them suitable for use in electro-optic devices. Furthermore, emission study showed a direct relation between fluorescence intensity and magnetic field induced orientation of the colloids. Finally, with their fast radiative recombination decay rates, the nanodiscs show luminescence properties that compare quite favourably with those of bulk CeF 3 . Therefore, these CeF 3 nanodiscs are very promising building blocks for the development and processing of photosensitive materials for sensor applications.

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Section: ■ Results and Discussionsupporting

confidence: 88%

Section: Resultssupporting

confidence: 66%

Section: ■ Results and Discussionmentioning

confidence: 77%

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Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs

et al. 2019

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Comparison of the nature of magnetism in α-Ni(OH)2 and β-Ni(OH)2

Rall

Seehra

Shah

et al. 2010

Journal of Applied Physics

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For the two stable phases of Ni(OH)2, viz. α-Ni(OH)2 and β-Ni(OH)2, structural and magnetic properties are compared employing x-ray diffraction (XRD), scanning electron microscopy/transmission electron microscopy (TEM/SEM), and variation of the magnetization (M) with temperatures (2–350 K) and magnetic fields (up to ≈65 kOe). Both phases crystallize in the layered hexagonal structure with a=3.04 Å (3.12 Å) and c=23.6 Å (4.67 Å) for the α(β) phase with clear evidence for turbostraticity in the α-phase. From TEM/SEM, the β-phase consists of nanoplates of dimensions 30(10)×3(1) nm, whereas the α-phase has flowerlike morphology with petal thickness ≈5(1) nm. The low-field M versus T data for the zero-field-cooled/field cooled cases bifurcates at Tp=25 K (13 K) for the β(α) phase. For T>Tp, Curie–Weiss variation of M versus T is observed yielding positive θ=20.6 K (32 K) with μ=2.95 μB (3.13 μB) for the Ni2+ ions in the β(α) phase. The M versus H data at 2 K shows antiferromagnetic (ferromagnetic) like variation for the β(α) phase with dM/dH showing peaks at Hc1=28 kOe and Hc2=55 kOe for the β-phase. It is concluded that β-Ni(OH)2 is a metamagnet for T<TN=25 K, whereas α-Ni(OH)2 is a hard ferromagnet with Tc=13 K and domain structure for H<5 kOe.

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Magnetically responsive bacterial cellulose: Synthesis and magnetic studies

Vitta

Drillon

Derory

2010

Journal of Applied Physics

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Bacterial cellulose with its porous network structure was used as a support to precipitate Ni nanoparticles by room temperature chemical reduction of Ni-chloride hexahydrate. The room temperature reduction in an aqueous environment results in the formation of crystalline Ni nanoparticles of size 10 to 60 nm inside the bacterial cellulose along with Ni(OH)2. The nanocrystals have an equiaxed shape and are found both as individual particles as well as small aggregates depending on the porous network structure of cellulose matrix. The bacterial cellulose does not undergo any change and retains its crystal structure even after chemical reduction reaction. The Ni loaded bacterial cellulose is found to be ferromagnetic at room temperature with a saturation magnetization of 2.81 emu g−1 which increases by an order of magnitude to 21.8 emu g−1 at 1.8 K. The coercive field also increases by two orders of magnitude from 28 G at 300 K to 2900 G at 1.8 K. The zero field cooled magnetization however exhibits a superparamagnetic behavior with a peak at 20 K, the blocking temperature and this behavior is observed even in ac magnetization. The magnetization decrease with increasing temperature up to 400 K, when extrapolated to high temperatures using a power law indicates a Curie transition at 500 K, much lower than the Curie temperature of bulk Ni. The fraction of isolated superparamagnetic nanoparticles present in the composite was estimated from the saturation magnetization and is found to be ∼88%. These results clearly highlight the presence of two separate magnetic phases, superparamagnetic, and ferromagnetic, and the role of various magnetic interactions in the collective magnetic behavior of Ni nanoparticles in the composite structure.

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Magneto-orientational properties of ionically stabilized aqueous dispersions of Ni(OH)2 nanoplatelets

Cited by 3 publications

References 28 publications

Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs

Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs

Comparison of the nature of magnetism in α-Ni(OH)2 and β-Ni(OH)2

Magnetically responsive bacterial cellulose: Synthesis and magnetic studies

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Magneto-orientational properties of ionically stabilized aqueous dispersions of Ni(OH)2 nanoplatelets

Cited by 3 publications

References 28 publications

Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF3 Nanodiscs

Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF3 Nanodiscs

Comparison of the nature of magnetism in α-Ni(OH)2 and β-Ni(OH)2

Magnetically responsive bacterial cellulose: Synthesis and magnetic studies

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Product

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Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs

Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF₃ Nanodiscs