1,721,219 research outputs found
(PRIN 2004) - Microscopia ottica a scansione a campo prossimo con analisi della polarizzazione della luce per microscopia magnetica e nano-magnetometria
No full textScopo di questo progetto è l'implementazione, su microscopi SNOM, dell'analisi della polarizzazione della luce per applicazioni allo
studio delle proprietà magnetiche della materia sulla scala di alcune decine di nanometri, trasferendo le tecniche classiche di
magnetometria magneto-ottica ad effetto Kerr (Magneto-Optical Kerr Effect, MOKE) o a rotazione Faraday a strumenti SNOM.
L’implementazione di queste tecniche renderebbe lo SNOM uno strumento complementare ad altre tecniche a scansione come i
microscopi a forza atomica o magnetica (AFM-MFM). Il progetto si basa sulla cooperazione di due gruppi, operanti uno presso
l’Università di Ferrara e l’altro presso il Politecnico di Milano, che hanno sviluppato nel corso degli anni vaste esperienze nel
campo dello studio delle proprietà di sistemi magnetici a bassa dimensionalità.
Il progetto è motivato dall’importanza della conoscenza della struttura e della dinamica dei domini magnetici con alta risoluzione
laterale per la comprensione dei fenomeni che si manifestano in strutture nanometriche. Questi sono all’origine di una grandissima
varietà di comportamenti magnetici di grande interesse sia per motivi legati alla fisica fondamentale, sia per motivi tecnologici, con
potenziali applicazioni in dispositivi per l'immagazzinamento dell'informazione, per testine di lettura e scrittura, per sensori e
dispositivi elettronici
Magnetic information in the light diffratted by Submicron-scale Periodic magnetic arrays
No full textThe experimental and theoretical aspects for obtaining the magnetic information carried by laser beams diffracted from an array of nano-sized magnetic objects is reviewed. Experimentally it will be shown thet the Magneto Optic Kerr Effect (MOKE) hysteresis loops recorded on diffracted beams can be quite different from those recorded in the reflected beam. We will show that the Diffracted-MOKE (D-MOKE) loops are proportional to the magnetic form factor, or equivalently, to the Fourier component of the magnetization corresponding to the reciprocal lattice vector of the diffracted beam. In conjunction with micromagnetic simulations D-MOKE provides powerful and non-destructive technique for investigating the magnetization reversal process in submicron sized magnetic particles
Diffracted-MOKE: What does it tell you?
No full textThe experimental and theoretical aspects of obtaining the magnetic information carried by laser beams diffracted from an array of nanosized magnetic objects are reviewed. Experimentally it will be shown that the magneto-optic Kerr effect (MOKE) hysteresis loops recorded for diffracted beams can be quite different from those recorded for the reflected beam. We will show that the diffracted MOKE (D-MOKE) loops are proportional to the magnetic form factor or, equivalently, to the Fourier component of the magnetization corresponding to the reciprocal lattice vector of the diffracted beam. In conjunction with micromagnetic simulations, the D-MOKE provides a powerful and non-destructive technique for investigating the magnetization reversal process in submicron-sized magnetic particles. The advantages and disadvantages of the D-MOKE technique will be compared to those of other techniques that yield related information (e.g. magnetic force microscopy, Lorentz electron microscopy and micromagnetic simulations)
SPINTRONIC MAGNETIC NANOPARTICLE SENSORS WITH ACTIVE AREA LOCATED ON A MAGNETIC DOMAIN WALL
No full textA sensor is described for detecting the presence of a magnetic nanoparticle (N). The sensor is arranged on a support (1), on which a plurality of non-magnetic contacts (Iin, GND, V1, V2) electrically conductively connected to the sensor is disposed. The contacts are adapted to be connected to means for measuring magnetoresistance. The sensor includes a planar ferromagnetic nanostructure (3), comprising a detection area (31) shaped as a strip bent to form a corner. The detection area is adapted to selectively assume, as a response to an applied magnetic field, a first spin configuration comprising a transverse “head-to- head” domain wall (TW), and a second spin configuration, wherein such domain wall (TW) is absent. The transition from the first configuration to the second configuration is affected by the proximity of a magnetic nanoparticle (N) to the detection area
Study of magnetic anisotropy and magnetism of Fe in Ni/Fe/Ni(111) trilayers by Mössbauer spectroscopy
No full textThe hyperfine field and the magnetic anisotropy of a Fe layer as a function of thickness have been investigated in several Ni/57Fex/Ni(1 1 1) trilayers with relatively thick Ni layers by Mössbauer spectroscopy. For Fe layers with thickness below 16 Å, the Mössbauer spectra show always the presence of two ferromagnetic phases with high-spin state. In the range between 6 and 8 Å, also a ferromagnetic phase with low-spin state and a paramagnetic phase have been found. The evolution of the mean hyperfine field of the 57Fe nuclei is used to study the Fe growth. A structural FCCBCC phase transition is found to begin with an iron thickness of 8 Å. The easy direction of the magnetization is found out-of-plane for Fe interlayer with FCC structure, and perfectly in plane for Fe interlayer with BCC structure. © 2002 Elsevier Science B.V. All rights reserved
Spintronic biosensors with active area localized on a domain wall
No full text.A sensor is described for detecting the presence of a magnetic nanoparticle (N). The sensor is arranged on a support (1), on which a plurality of non-magnetic contacts (Iin, GND, V1, V2) electrically conductively connected to the sensor is disposed. The contacts are adapted to be connected to means for measuring magnetoresistance. The sensor includes a planar ferromagnetic nanostructure (3), comprising a detection area (31) shaped as a strip bent to form a corner. The detection area is adapted to selectively assume, as a response to an applied magnetic field, a first spin configuration comprising a transverse “head-to- head” domain wall (TW), and a second spin configuration, wherein such domain wall (TW) is absent. The transition from the first configuration to the second configuration is affected by the proximity of a magnetic nanoparticle (N) to the detection area
Magnetic interface anisotropy in Ni/Fe/Ni(111) trilayers
No full textThe direction of the spins of Ni capping layers and the 57Fex interlayer have been studied in Ni/57Fex/Ni(1 1 1) films by magneto-optic-vector Kerr and Mössbauer spectroscopy. It was found that the magnetization direction of the Ni follows the orientation of that of the Fe, and that there is an unusual rotation of the magnetization from the in-plane to out-of-plane in the pseudomorphic range of the Fe growth. The effect of the competition between perpendicular surface anisotropy and the magnetostatic energy is discusse
Magnetic information in the light diffracted by submicron-scale periodic magnetic arrays
No full textThe experimental and theoretical aspects for obtaining the magnetic information carried by laser beams diffracted from an array of nano-sized magnetic objects is reviewed. Experimentally it will be shown thet the Magneto Optic Kerr Effect (MOKE) hysteresis loops recorded on diffracted beams can be quite different from those recorded in the reflected beam. We will show that the Diffracted-MOKE (D-MOKE) loops are proportional to the magnetic form factor, or equivalently, to the Fourier component of the magnetization corresponding to the reciprocal lattice vector of the diffracted beam. In conjunction with micromagnetic simulations D-MOKE provides powerful and non-destructive technique for investigating the magnetization reversal process in submicron sized magnetic particles
Combinatorial testing for feature models using CitLab
No full textFeature models are commonly used to represent product lines and systems with a set of features interrelated each others. Test generation from feature models, i.e. generating a valid and representative subset of all the possible product configurations, is still an open challenge. A common approach is to build combinatorial interaction test suites, for instance achieving pairwise coverage among the features. In this paper we show how standard feature models can be translated to combinatorial interaction models in our framework CITLAB, with all the advantages of having a combinatorial testing environment (in terms of a clear semantics, editing facilities, language for seeds and test goals, and generation algorithms). We present our translation which gives a precise semantics to feature models and it tries to minimize the number of parameter and constraints while preserving the original semantics of the feature model. Experiments show the advantages of our approach
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