Magnetic Configurations of 30 nm Iron Nanocubes Studied by Electron Holography

Snoeck, E.; Gatel, Christophe; Lacroix, Lise‐Marie; Blon, Thomas; Lachaize, Sébastien; Carrey, Julian; Respaud, Marc; Chaudret, Bruno

doi:10.1021/nl801998x

Cited by 119 publications

(118 citation statements)

References 40 publications

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“…For the evolution of the magnetic configuration, many techniques in a TEM are available among which the electron holography has proven its efficiency on NPs [64].Study on NPs benefit from all the technical and experimental developments in TEM for some years now, for structural and chemical aspects but also for the determination of local physical properties. …”

Section: Transmission Electron Microscopy Temmentioning

confidence: 99%

Engineered inorganic core/shell nanoparticles

et al. 2014

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It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview 2 of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

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Section: Transmission Electron Microscopy Temmentioning

confidence: 99%

Engineered inorganic core/shell nanoparticles

et al. 2014

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“…Stacking several disks provides additional degrees of freedom to control the precessional modes or the spectrum purity, for instance allowing to consider vortices with cores aligned parallel or antiparallel [13]. While coupled nanocubes had been imaged by electron holography in the case of parallel cores [14], stacked disks could be imaged recently with magnetic tomography holography, revealing fine details in the case of (repulsive) antiparallel cores [15]. The topological identity of such structures with so-called merons has been highlighted [16].…”

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confidence: 99%

Quantitative analysis of shadow x-ray magnetic circular dichroism photoemission electron microscopy

et al. 2015

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Shadow X-ray Magnetic Circular Dichroism Photo-Emission Electron Microscopy (XMCD-PEEM) is a recent technique, in which the photon intensity in the shadow of an object lying on a surface, may be used to gather information about the three-dimensional magnetization texture inside the object. Our purpose here is to lay the basis of a quantitative analysis of this technique. We first discuss the principle and implementation of a method to simulate the contrast expected from an arbitrary micromagnetic state. Text book examples and successful comparison with experiments are then given. Instrumental settings are finally discussed, having an impact on the contrast and spatial resolution : photon energy, microscope extraction voltage and plane of focus, microscope background level, electric-field related distortion of three-dimensional objects, Fresnel diffraction or photon scattering.Progress is continuous in the decreasing size and increasing complexity of nanosized magnetic systems being designed for either fundamental science or devices. Magnetic microscopies are crucial tools to monitor and understand the properties of such systems. Various types of information are desirable to gather, leading to multiple criteria to classify microscopies: spatial and time resolution, compatibility with environmental parameters such as variable temperature and applied magnetic field, requirements on the sample preparation and compatibility for ex-situ processing such as lithography, correlation with structural information, elemental sensitivity, quantity measured (magnetization, induction, stray field etc.), sensitivity. The most common magnetic microscopies offering spatial resolution below 50 nm and direct sensitivity to magnetization are X-ray Magnetic Circular Dichroism PhotoEmission Electron Microscopy (XMCD-PEEM) [ [7][8][9].Yet another criterion is the volume of the sample probed. This criterium is gaining in importance in the context of the emergence of three-dimensional (3D) magnetic objects and textures. The distribution of magnetization may be truly 3D if along the three directions in space the size of a system lies above magnetic characteristic length scales, such as the dipolar exchange length ∆ d for soft magnetic materials, or the anisotropy exchange length ∆ u for a hard magnetic material [10]. While this is obviously fulfilled in macroscopic materials, the complexity of magnetic textures is such that it cannot be measured in detail, and besides it cannot be controlled to achieve specific functions. The progress in nanofabrication techniques now allows to design suitable systems, both with top-down and bottom-up approaches. Let us give some examples. Flat magnetic elements are basic building blocks in spintronics, being patterned with great 2D versatility with thin film and lithography technologies. Large lateral dimensions may give rise to 2D magnetic textures, such as the so-called vortex state in disks [11]. Such textures are being investigated to design RF oscillator components, relying on the gyrotropic motion ...

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“…27 Their enhanced magnetic properties are based on their magnetic dipole interaction between the nanocrystals. Characteristic properties of SLSs assembled with IIVI or IIIV semiconductor nanocrystals have also been reported.…”

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confidence: 99%