The vapour-phase growth of thin nickel crystal platelets

Vojdani, S.; White, E. A. D.

doi:10.1007/bf00555052

Cited by 6 publications

(2 citation statements)

References 7 publications

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“…Among several strategies developed for the vapor-phase synthesis of 2D and 1D nanostructures, in principle, it is possible to process any solid material into 2D and 1D nanostructures by controlling the supersaturation at relatively low levels, respectively. − For example, Sears et al in a series of whiskers grown from vapor phase studies on various solid materials such as Ag and Zn found that the experimentally estimated supersaturation for the growth of 1D whisker is less than or approximately equal to the calculated supersaturation for the 2D nucleation. Above these experimental supersaturations the growth of massive crystals, which presumably involves surface nucleation, occurs experimentally and 1D whiskers do not grow .…”

Section: Resultsmentioning

confidence: 99%

Use of the Carbothermal Route to Prepare Anisotropic Single-Crystal Platinum Nanostructures with Low Resistivity

Chen

2009

Crystal Growth & Design

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We have used a carbothermal process in the absence of a catalyst or template to prepare two-dimensional (2D) platinum (Pt) nanoplatelets and one-dimensional (1D) Pt nanobelts on sapphire surfaces. This paper describes the first examples of the growth of Pt nanobelts and mesobelts. It appears that the presence of adequate quantities of diamond and Y 2 O 3 powder at a molar ratio was a critical factor controlling the Pt gas species to form nanobelts at a relative low level of supersaturation. When the growth time was 15 h, we obtained ultralong (0.5 mm) mesobelts and microsheets. Electrical measurements indicated that the single-crystal Pt nanobelt had an extremely low resistivity of 16.8 µΩ cm and a failure current density of greater than 1 × 10 7 A cm -2 . These unique Pt nanobelts are potentially attractive nanoscale building blocks for use as interconnects in nanoelectronic devices.Research into noble-metal nanostructures is stimulated by the fascinating size-and shape-dependent properties of these nanomaterials. Because of their unique and tunable properties, they hold promise for various applications in optics, electronics, information storage, biological labeling, and imaging. 1 Platinum (Pt) is one of the most important noble metals, 2-4 especially for its application in the fields of molecular scale electronic devices, 5 biosensors, 6 and catalysts. 7,8 For example, because platinum is inert, highly thermally stable in air, and does not cause contamination of the integrated circuit, it is the most common choice for use in integrated circuit repair and modification and bottom electrode. 9 Also, because of its nice performance toward the detection of hydrogen peroxide, a typical enzymatic product, platinum electrodes, and platinum nanostructure modified electrodes have been widely used for fabrication of biosensors. 10 Because Pt has a face-centered cubic (fcc) structure, there is no crystallographic driving force for anisotropic growth. As a result, Pt atoms generally assemble to form faceted spheres (e.g., singlecrystal cuboctahedrons) 11 and, in particular, few reports exist describing the growth of two-dimensional (2D) and one-dimensional (1D) Pt nanostructures. In spite of that, it is common for other fcc metals (like Ag, Au) to form 2D nanostructures, such as triangular and hexagonal platelets, when transition-metal colloids are prepared in solution through the reduction of metal salts. 12-14 Most reports on the preparation of Pt nanostructures have been limited to the synthesis of nanoparticles (NPs) or polycrystalline nanorods using either solution-phase techniques 15 or template-directed synthesis 16 for examples of synthesized 2D and 1D Pt nanostructures, respectively. Tan et al. prepared 2D Pt NPs by the reduction of their salts with a weak reductant -potassium bitartrate. In their study, Pt NPs have two dominant shape distributions, triangular and square. 17 For an instance of synthesized 1D Pt nanostructures, Zhao et al. synthesized polycrystalline Pt nanowire array electrode by dc electrodeposi...

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Section: Resultsmentioning

confidence: 99%

Use of the Carbothermal Route to Prepare Anisotropic Single-Crystal Platinum Nanostructures with Low Resistivity

Chen

2009

Crystal Growth & Design

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“…This work describes preliminary results of a study of stripe domains in nickel platelets by means of Lorentz microscopy , using the AEI EM7 lMeV microscope installed at the Imperial College (Harrison, Leaver & Swann, 1972) to examine platelets up to 640 nm thick. Thin, highly perfect platelets of pure nickel grown by vapour transport (Vojdani & White, 1969) provide nearly ideal specimens for the study of micromagnetic structures, such as magnetic domain walls and stripe domains. The platelets grow in crystallographically bounded shapes, the major surfaces being invariably (001).…”

Section: Introductionmentioning

confidence: 99%

Micromagnetic structures in single crystal specimens of intermediate thickness studied by Lorentz microscopy

Harrison

Leaver

1973

Journal of Microscopy

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Stripe domains in (001) nickel occur in a variety of structures due to the large number of easy directions present. We have given below a tentative analysis of two of these structures, not previously studied by Lorentz microscopy. In particular it has been shown that, as used hitherto, the technique has not been a reliable method of observing stripe domains since some structures may be invisible until the specimen is tilted.

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The analysis of two-dimensional domain wall structures by Lorentz microscopy

Harrison

Leaver

1973

Phys. Stat. Sol. (a)

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The technique for the study of the inhomogeneous magnetisation components of domain walls by Lorentz microscopy [15] is extended to cover structures which are not stray‐field‐free. Permitted forms for the distributions of the inhomogeneous components are derived and variants of the forms of vortex structures are considered. Results are presented of the application of the technique to 90° and 180° walls in (001) nickel platelets with thicknesses in the range 530 to 4230 Å. Below the critical thickness for stripe domain nucleation (≈︁2800 Å), 90° walls exhibit a pure Néel structure, as do 180° walls in thicknesses up to about 1000 Å. In the thickness range 1000 to 2800 Å 180° walls conform closely to the predicted vortex structure [11, 12]. These 180° walls are found to be subdivided through changes in the vortex corresponding to the predicted variants. Structures are proposed for the junctions in the subdivided walls, one of which may contain a Bloch point. At thicknesses greater than approximately 2800 Å, stripe domains are found to seriously modify the wall structures.

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The vapour-phase growth of thin nickel crystal platelets

Cited by 6 publications

References 7 publications

Use of the Carbothermal Route to Prepare Anisotropic Single-Crystal Platinum Nanostructures with Low Resistivity

Use of the Carbothermal Route to Prepare Anisotropic Single-Crystal Platinum Nanostructures with Low Resistivity

Micromagnetic structures in single crystal specimens of intermediate thickness studied by Lorentz microscopy

The analysis of two-dimensional domain wall structures by Lorentz microscopy

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