Self-organized semiconductor surfaces as templates for nanostructured magnetic thin films
TL;DR: In this article, a variety of patterns with different symmetries can be obtained, as will be summarized for the model system of SiGe on Si(001) for the case of semiconductor heteroepitaxy, where strain relief leads to the formation of nanofaceted three-dimensional crystallites.
Abstract: Spontaneous pattern formation during epitaxial growth or ion erosion of semiconductor wafers offers an elegant route towards large-area nanostructured surfaces. In homoepitaxy, kinetics may result in rather uniform three-dimensional islands. In the case of semiconductor heteroepitaxy, strain relief leads to the formation of nanofaceted three-dimensional crystallites, which may self-organize into quasiperiodic arrays. By tuning substrate miscut and film thickness, or growing superlattices, a variety of patterns with different symmetries can be obtained, as will be summarized for the model system of SiGe on Si(001). Since these self-organized nanostructure arrays cover the entire wafer on which they are grown, they can serve as large-area nanopatterned substrates for subsequent deposition of magnetic thin films. It will be demonstrated that such templates allow the study of correlations between magnetic and chemical interfacial roughness, as well as the influence of pattern symmetry on the magnetic anisotropy of thin Co films. Furthermore, shadow deposition of magnetic material onto specially faceted nanostructure arrays allows the fabrication of nanomagnet arrays and the study of their magnetic properties.
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TL;DR: Streubel et al. as mentioned in this paper presented a review of the application potential of three-dimensional-shaped objects as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices.
Abstract: Author(s): Streubel, R; Fischer, P; Kronast, F; Kravchuk, VP; Sheka, DD; Gaididei, Y; Schmidt, OG; Makarov, D | Abstract: Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii-Moriya-like interaction. As a consequence, a family of novel curvature-driven effects emerges, which includes magnetochiral effects and topologically induced magnetization patterning, resulting in theoretically predicted unlimited domain wall velocities, chirality symmetry breaking and Cherenkov-like effects for magnons. The broad range of altered physical properties makes these curved architectures appealing in view of fundamental research on e.g. skyrmionic systems, magnonic crystals or exotic spin configurations. In addition to these rich physics, the application potential of three-dimensionally shaped objects is currently being explored as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices. These recent developments ranging from theoretical predictions over fabrication of three-dimensionally curved magnetic thin films, hollow cylinders or wires, to their characterization using integral means as well as the development of advanced tomography approaches are in the focus of this review.
280 citations
TL;DR: In this paper, two major trends of molecular spintronics are the design of molecular analogs of the inorganic spintronic structures, and the evolution towards single-molecule spintrons.
Abstract: Molecular spintronics is a new and emerging sub-area of spintronics that can benefit from the achievements obtained in molecular electronics and molecular magnetism. The two major trends of this area are the design of molecular analogs of the inorganic spintronic structures, and the evolution towards single-molecule spintronics. The former trend opens the possibility to design cheaper spintronic devices compatible with plastic technology, while the second takes advantage of the possibility to tailor molecules with control down to the single spin. In this highlight these two trends will be compared with the state-of-the-art achieved in the conventional inorganic spintronic systems.
153 citations
TL;DR: In this article, the main experimental results and applications are described under the light of the recently established evidence on the key role played by simultaneous impurity incorporation during irradiation, which has opened a new scenario for an improved understanding of the phenomenon.
Abstract: In recent years Ion Beam Sputtering (IBS) has revealed itself as a powerful technique to induce surface nanopatterns with a large number of potential applications. These structures are produced in rather short processing times and over relatively large areas, for a wide range of materials, such as metals, insulators, and semiconductors. In particular, silicon has become a paradigmatic system due to its technological relevance, as well as to its mono-elemental nature, wide availability, and production with extreme flatness. Thus, this review focuses on the IBS nanopatterning of silicon surfaces from the experimental and the theoretical points of view. First, the main experimental results and applications are described under the light of the recently established evidence on the key role played by simultaneous impurity incorporation during irradiation, which has opened a new scenario for an improved understanding of the phenomenon. Second, the progress and state-of-art of the theoretical descriptions of the IBS nanopatterning process for this type of targets are discussed. We summarize the historical approach to IBS through simulation techniques, with an emphasis on recent information from Molecular Dynamics methods, and provide a brief overview of the earlier and most recent continuum models for pure and compound systems.
139 citations
TL;DR: In this paper, the authors provide an overview of the most recent studies on the production of nanoripple, nanohole and nanodot periodic nanostructures by IBS, with special attention to the comparison between experiments and (continuum) models, and with a focus on those issues that remain open or ambiguous.
Abstract: The production of self-organized surface nanopatterns by ion beam sputtering (IBS) at low (<10 keV) and intermediate (10–100 keV) energies has emerged in the last decade as a promising bottom-up nanostructuring tool. The technique is remarkably universal, being applicable to metals, semiconductors or insulators, and it enables large degree of control over the main pattern features with high throughput (it requires low process time and can be used over extended areas). However, there is a wide scatter in the experimental results obtained as a function of system type and process parameters. In parallel, diverse theoretical models have been developed that differ in their capabilities to reproduce such a wide range of experimental features. We provide an overview of the most recent studies on the production of nanoripple, nanohole and nanodot periodic nanostructures by IBS, with special attention to the comparison between experiments and (continuum) models, and with a focus on those issues that remain open or, at least, ambiguous. The pattern properties to be considered are those of potential increased technological importance, such as the variation of size, shape, distance and ordering of the nanostructures as a function of parameters such as ion energy, target temperature and sputtering time (i.e., fluence). Finally, reported and proposed applications of IBS nanopatterns are briefly presented showing, in this way, the high-potential functionality of IBS nanostructured surfaces.
79 citations
01 Jan 2009
TL;DR: In this article, a large-scale ab initio study of size, shape, and doping effects on electronic structure of nanocrystals was carried out, and the results showed that nanocrystal-based polymer composites are novel functional materials.
Abstract: Chapter 1: Fabrication of oxide nanoparticles by ion implantation and thermal oxidation Hiroshi Amekura Chapter 2: Design of solution-grown ZnO nanostructures Thierry Pauporte Chapter 3: Self-assembled metal nanostructures in semiconductor structures Francesco Ruffino Chapter 4: Nanocrystal based polymer composites as novel functional materials Marinella Striccoli Chapter 5: Large-scale ab initio study of size, shape, and doping effects on electronic structure of nanocrystals Jingbo Li Chapter 6: Chaotic behavior appearing in dynamic motions of nanoscale particles Kouji Miura Chapter 7: Hydrogen concentration, bonding configuration and electron emission properties of polycrystalline diamond films: from micro- to nano-metric grain size Alon Hoffman Chapter 8: Super-resolution optical effects of nanoscale nonlinear thin film structure and ultrahigh density information storage Jingsong Wei Chapter 9: Spin-transfer and current-induced spin dynamics in spin valves: diffusive transport regime Martin Gmitra Chapter 10 : Self-organized surface nanopatterning by ion beam sputtering Raul Gago Chapter 11: Area-selective depositions of self-assembled monolayers on patterned SiO2/Si surfaces Changhsun Wang Chapter 12: Virtual synthesis of electronic nanomaterials: Fundamentals and prospects Liudmila Pozhar
45 citations
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