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Your search keyword '"Iannotti, V."' showing total 7 results
Start Over Author "Iannotti, V." Topic ferromagnetism
7 results on '"Iannotti, V."'

1. Magnetic and structural investigation of growth induced magnetic anisotropies in Fe50Co50 thin films.

Author

Tamisari, M., Ausanio, G., Guidi, V., Iannotti, V., Neri, I., Spizzo, F., and Vavassori, P.

Subjects
MAGNETIC properties, POLYCRYSTALS, MAGNETIZATION, FERROMAGNETISM, MAGNETISM
Abstract

In this paper, we investigate the magnetic properties of Fe50Co50 polycrystalline thin films, grown by dc-magnetron sputtering, with thickness (t) ranging from 2.5 nm up to 100 nm. We focused on the magnetic properties of the samples to highlight the effects of possible intrinsic stress that may develop during growth, and their dependence on film thickness. Indeed, during film deposition, due to the growth technique and growth conditions, a metallic film may display an intrinsic compressive or tensile stress. In our case, due to the Fe50Co50 magnetolastic properties, this stress may in its turn promote the development of magnetic anisotropies. Samples magnetic properties were monitored with a SQUID magnetometer and a magneto-optic Kerr effect apparatus, using both an in-plane and an out-of-plane magnetic field. Magnetoresistance measurements were collected, as well, to further investigate the magnetic behavior of the samples. Indications about the presence of intrinsic stress were obtained accessing samples curvature with an optical profilometer. For t ≤ 20 nm, the shape of the in-plane magnetization loops is squared and coercivity increases with t, possibly due to fact that, for small t values, the grain size grows with t. The magnetoresistive response is anisotropic in character. For t > 20 nm, coercivity smoothly decreases, the approach to saturation gets slower and the shape of the whole loop gets less and less squared. The magnetoresistive effect becomes almost isotropic and its intensity increases of about one order of magnitude. These results suggest that the magnetization reorientation process changes for t > 20 nm, and are in agreement with the progressive development of an out-of-plane easy axis. This hypothesis is substantiated by profilometric analysis that reveals the presence of an in-plane compressive stress. [ABSTRACT FROM AUTHOR]

Published
2013
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2. Giant magnetic induction in magneto-elastic resonators and its application for magnetic field sensors

Author

Ausanio, G., Iannotti, V., and Lanotte, L.

Subjects
*RESONATORS, *MAGNETIC devices, *DETECTORS, *ELECTROMAGNETIC induction, *MAGNETOSTRICTION, *MAGNETIC fields, *PERFORMANCE evaluation, *FERROMAGNETISM
Abstract

Abstract: The competitive performance of an optimized magneto-elastic resonator as sensor of a local magnetic field is reported. The resonator core is constituted by an amorphous ferromagnetic ribbon in which stationary waves are established by means of magneto-elastic coupling. The appropriate choice of the ribbon composition and the use of a special heat treatment are determinant on the sensor response. In proper conditions, the sensitive parameter, namely the electromotive force (root mean square value) induced in a miniaturized pick-up coil, has relative changes of 104 for a magnetic field increment of 10A/m. Magnetic induction fields as small as 10−8 T can be measured with a technology simpler than in other used devices. A good linearity of the sensor response at low field (from 0A/m up to 50A/m) is demonstrated too. [Copyright &y& Elsevier]

Published
2009
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3. Consistency between morphology and magnetization data in studying the effect of production parameters in Nd90−xFexAl10 (<f>x=35–50</f>) melt spun ribbons

Author

Ausanio, G., Chiriac, H., Iannotti, V., Hison, C., Lanotte, L., and Lupu, N.

Subjects
*MICROSTRUCTURE, *MAGNETIZATION, *ATOMIC force microscopy, *FERROMAGNETISM
Abstract

The microstructure morphology of Nd90−xFexAl10 (x=35−50) ribbons, obtained by melt spinning at two surface wheel velocities, was investigated by atomic force microscopy. A direct dependence of microstructure homogeneity on both production parameters and Nd content was evidenced. In particular high surface wheel velocity promotes an amorphous structure while low Nd content promotes grain formation. At the same time, the temperature dependence of magnetization, in field cooled and zero field cooled samples, shows the coexistence of short-range spin glass-like interactions and long-range ferromagnetic order, which are also coherent with the morphologic characteristics. [Copyright &y& Elsevier]

Published
2003
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4. Torsional oscillation monitoring by means of a magnetoelastic resonator: modeling and experimental functionalization to measure viscosity of liquids

Author

Giovanna Tomaiuolo, Vincenzo Iannotti, Luciano Lanotte, Giovanni Ausanio, Luca Lanotte, Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Lanotte, L., Ausanio, G., Iannotti, V., and Tomaiuolo, G.

Subjects
Magnetoelastic resonatorLow shear ratesa, UHT milk, Work (thermodynamics), Materials science, Low shear ratesa, Rheometer, lait uht, 02 engineering and technology, Low frequency, modèle, 01 natural sciences, magnetic resonance, Resonator, Viscosity, [SDV.IDA]Life Sciences [q-bio]/Food engineering, 0103 physical sciences, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Electrical and Electronic Engineering, Composite material, Instrumentation, Magnetoelastic resonator, 010302 applied physics, numerical models, Oscillation, Viscosity measurement, viscosité, Metals and Alloys, oscillation, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, résonance magnétique, monitoring, Amplitude, Ferromagnetism, Low shear rate, viscosity, Damped oscillation, 0210 nano-technology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract

A new application of a high sensitivity magnetoelastic resonator able to measure period and damping constant of low frequency torsional oscillation is described and validated by experimental tests. The sensitive parameter is the amplitude of resonant magnetoelastic waves in the soft ferromagnetic core (Fe 62.5 Co 6 Ni 7.5 Zr 6 Cu 1 Nb 2 B 15 amorphous ribbon). The theoretical model of the device has been developed, correlating torsional oscillations to the friction force applied by the fluid in which they occur. Thus, an accurate indirect evaluation of fluid viscosity has been demonstrated. The main prerogative of the proposed sensor is to work without contact with the oscillating mechanism. As experimental validation, viscosity of UHT milk was measured versus different fat content. The experimental comparison with a standard rheometer demonstrates the new device competitiveness in the measure of low viscosity fluids at low share rate. Moreover, the detected behaviors at increasing temperature are in agreement with previous literature. In perspective, the new magnetoelastic resonators application can be very ductile and effective in on-line monitoring of viscosity change with time to control composition, degradation or contamination of liquids.

Published
2019
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5. Particle dimension effects on magnetization and strain sensitivity for a composite of nickel particles in silicone matrix

Author

Lanotte, L., Ausanio, G., Hison, C., Iannotti, V., and Luponio Jr, C.

Subjects
*COMPOSITE materials, *MAGNETIZATION, *NICKEL, *FERROMAGNETISM
Abstract

Samples of composite material made of Ni ellipsoidal particles (with a fixed eccentricity but different major axis dimensions) uniformly dispersed in a silicone matrix were produced and characterized by both magnetization cycles and strain sensitivity of magnetization tests. It was theoretically justified and experimentally shown that at constant Ni percentage, in the case of nanometric size particles, higher coercive and saturation fields and a higher strain sensitivity of the magnetization intensity in comparison with the case of micrometric particles are obtained. [Copyright &y& Elsevier]

Published
2004
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6. Potential application of innovative magnetoelastic resonators for vibration detection

Author

Giovanni Ausanio, M Inverno, Luciano Lanotte, Roberto Germano, R Sorrentino, C. Luponio, Amleto D'agostino, Vincenzo Iannotti, Ausanio, Giovanni, Iannotti, V, Luponio, C, Lanotte, L, Germano, R, D'Agostino, A, Inverno, M, and Sorrentino, R.

Subjects
Amorphous metal, Materials science, Condensed matter physics, Metals and Alloys, Condensed Matter Physics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Magnetic field, Core (optical fiber), Vibration, Resonator, Ferromagnetism, Dimension (vector space), Sensitivity (control systems), Electrical and Electronic Engineering, Instrumentation
Abstract

Recently, a new ferromagnetic amorphous alloy Fe62.5Co6Ni7.5Zr6Cu1Nb2B15 was produced which was used as core in new magnetoelastic wave resonators. In particular, the achievement of the following innovative properties were obtained: (1) low dimension; (2) zero polarising magnetic field in standard working condition; (3) high sensitivity to local change of magnetic field; (4) low costs. A very high sensitivity to little changes of magnetic field was obtained; it can be used to detect vibrations in the range of mechanical oscillations (1–500 Hz).

Published
2001

7. Magnetic magnetoelastic and structural properties of Co82P18 Fe80B13Si4C3 and Fe73.5Cu1Nb3Si15.5B7 amorphous ribbons after consecutive heat cycles in vacuum

Author

Luciano Lanotte, G. Ausanio, Vincenzo Iannotti, Roberto Germano, Ausanio, Giovanni, Germano, R, Iannotti, V, Lanotte, L., G., Ausanio, R., Germano, Iannotti, Vincenzo, and Lanotte, Luciano

Subjects
Materials science, Magnetoelastic wave amplitude, Condensed matter physics, Annealing (metallurgy), General Physics and Astronomy, equipment and supplies, Amorphous solid, law.invention, Annealing, Amorphous ferromagnetic ribbon, Condensed Matter::Materials Science, Differential scanning calorimetry, Amplitude, Nuclear magnetic resonance, Ferromagnetism, law, Condensed Matter::Strongly Correlated Electrons, Thermal stability, Crystallization, human activities
Abstract

Amorphous ferromagnetic ribbons, with basic differences in production technique, in thermal stability and devetrification modality, were investigated to compare some of their magnetic, magnetoelastic and structural properties after repeated annealing cycles in vacuum. In particular, differences in structural relaxation, measured by Differential Scanning Calorimetry, were related to effects on magnetic permeability, magnetoelastic wave amplitude and crystallization occurrence.

Published
1998

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