Search results for "Nanoscopic scale"

Ptychographic imaging and micromagnetic modeling of thermal melting of nanoscale magnetic domains in antidot lattices

2020

CA extern Antidot lattices are potential candidates to act as bit patterned media for data storage as they are able to trap nanoscale magnetic domains between two adjacent holes. Here, we demonstrate the combination of micromagnetic modeling and x-ray microscopy. Detailed simulation of these systems can only be achieved by micromagnetic modeling that takes thermal effects into account. For this purpose, a Landau-Lifshitz-Bloch approach is used here. The calculated melting of magnetic domains within the antidot lattice is reproduced experimentally by x-ray microscopy. Furthermore, we compare conventional scanning transmission x-ray microscopy with resolution enhanced ptychography. Hence, we …

Multiscale model approach for magnetization dynamics simulations

2016

Simulations of magnetization dynamics in a multiscale environment enable the rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization…

Nanoscale Etching of GaAs and InP in Acidic H<sub>2</sub>O<sub>2</sub> Solution: A Striking Contrast in Kinetics and Surface …

2018

In this study of nanoscale etching for state-of-the-art device technology the importance of the nature of the surface oxide, is demonstrated for two III-V materials. Etching kinetics for GaAs and InP in acidic solutions of hydrogen peroxide are strikingly different. GaAs etches much faster, while the dependence of the etch rate on the H+ concentration differs markedly for the two semiconductors. Surface analysis techniques provided information on the surface composition after etching: strongly non-stoichiometric porous (hydr)oxides on GaAs and a thin stoichiometric oxide that forms a blocking layer on InP. Reaction schemes are provided that allow one to understand the results, in particular…

Solid-State Molecular Nanomagnet Inclusion into a Magnetic Metal-Organic Framework: Interplay of the Magnetic Properties.

2015

Single-ion magnets (SIMs) are the smallest possible magnetic devices and are a controllable, bottom-up approach to nanoscale magnetism with potential applications in quantum computing and high-density information storage. In this work, we take advantage of the promising, but yet insufficiently explored, solid-state chemistry of metal-organic frameworks (MOFs) to report the single-crystal to single-crystal inclusion of such molecular nanomagnets within the pores of a magnetic MOF. The resulting host-guest supramolecular aggregate is used as a playground in the first in-depth study on the interplay between the internal magnetic field created by the long-range magnetic ordering of the structur…

Non-conventional Ce:YAG nanostructures via urea complexes

2019

AbstractCe:YAG nanostructures (Ce:YAG = Cerium in Yttrium Aluminium Garnet), easy to control and shape, have been prepared via templating approach using natural and synthetic materials (i.e. paper, cotton wool and glass wool) previously soaked with a gel-like metals precursor and then thermally treated to achieve the wished morphology. The final material, otherwise difficult to process, can be easily moulded, it is lightweight, portable and forms, at the nanoscale, homogeneous layers of interconnected but not agglomerated nanoparticles (15 ± 5 nm). Using the same synthetic route, called Urea-Glass-Route, but in absence of a template, extremely pure Ce:YAG nanoparticle (45 ± 5 nm) can be als…

Heat- and pH-induced BSA conformational changes, hydrogel formation and application as 3D cell scaffold

2016

Aggregation and gelation of globular proteins can be an advantage to generate new forms of nanoscale biomaterials based on the fibrillar architecture. Here, we report results obtained by exploiting the proteins' natural tendency to self-organize in 3D network, for the production of new material based on BSA for medical application. In particular, at five different pH values the conformational and structural changes of the BSA during all the steps of the thermal aggregation and gelation have been analyzed by FTIR spectroscopy. The macroscopic mechanical properties of these hydrogels have been obtained by rheological measurements. The microscopic structure of the gels have been studied by AFM…

Rational Design of Thermoresponsive Microgel Templates with Polydopamine Surface Coating for Microtissue Applications.

2021

Functional microgels provide a versatile basis for synthetic in vitro platforms as alternatives to animal experiments. The tuning of the physical, chemical, and biological properties of synthetic microgels can be achieved by blending suitable polymers and formulating them such to reflect the heterogenous and complex nature of biological tissues. Based on this premise, this paper introduces the development of volume-switchable core-shell microgels as 3D templates to enable cell growth for microtissue applications, using a systematic approach to tune the microgel properties based on a deep conceptual and practical understanding. Microscopic microgel design, such as the tailoring of the microg…

Detection of Amyloid-β Fibrils Using Track-Etched Nanopores: Effect of Geometry and Crowding

2021

Several neurodegenerative diseases have been linked to proteins or peptides that are prone to aggregate in different brain regions. Aggregation of amyloid-β (Aβ) peptides is recognized as the main cause of Alzheimer's disease (AD) progression, leading to the formation of toxic Aβ oligomers and amyloid fibrils. The molecular mechanism of Aβ aggregation is complex and still not fully understood. Nanopore technology provides a new way to obtain kinetic and morphological aspects of Aβ aggregation at a single-molecule scale without labeling by detecting the electrochemical signal of the peptides when they pass through the hole. Here, we investigate the influence of nanoscale geometry (conical an…

Host Solids Containing Nanoscale Anion-Binding Pockets and Their Use in Selective Sensing Displacement Assays

2005

Size-selective incorporation of DNA nanocages into nanoporous antimony-doped tin oxide materials.

2011

A conductive nanoporous antimony-doped tin oxide (ATO) powder has been prepared using the sol-gel method that contains three-dimensionally interconnected pores within the metal oxide and highly tunable pore sizes on the nanoscale. It is demonstrated that these porous materials possess the capability of hosting a tetrahedral-shaped DNA nanostructure of defined dimensions with high affinity. The tunability of pore size enables the porous substrate to selectively absorb the DNA nanostructures into the metal oxide cavities or exclude them from entering the surface layer. Both confocal fluorescence microscopy and solution FRET experiments revealed that the DNA nanostructures maintained their int…