A5046034707- Nuclear Physics and Applications
- Astrophysical Phenomena and Observations
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Shape Memory Alloy Transformations
- Magnetic and transport properties of perovskites and related materials
- High-pressure geophysics and materials
- Advanced X-ray Imaging Techniques
- Particle Detector Development and Performance
- Magnetic properties of thin films
- Heusler alloys: electronic and magnetic properties
- Crystallography and Radiation Phenomena
- Gamma-ray bursts and supernovae
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic Properties and Applications
- Particle Accelerators and Free-Electron Lasers
- Magnetic Properties of Alloys
- High Entropy Alloys Studies
- Magnetic confinement fusion research
- Quantum, superfluid, helium dynamics
- Superconducting Materials and Applications
- Physics of Superconductivity and Magnetism
- X-ray Diffraction in Crystallography
- Intermetallics and Advanced Alloy Properties
- Diamond and Carbon-based Materials Research
Institut Laue-Langevin
2012-2023
Institut Langevin
2004-2009
University of Sassari
2008
Université de Technologie de Compiègne
2001
Centre National de la Recherche Scientifique
1995-1996
A large inverse magnetocaloric effect has been observed in a Ni45Co5Mn37.5In12.5 single crystal at room temperature. Magnetothermal measurements performed different magnetic fields reveal nonmagnetic to ferromagnetic transition correlated with the austenite-martensite phase transformation. The Heusler shows entropy change of 30 J/Kg K an applied field 7 T during first-order magnetostructural 355 K. It leads net refrigerant capacity 267 T, which is very encouraging for refrigeration applications.
We investigate low-temperature spin correlations in the metallic frustrated magnet β-Mn1-xCox. Single-crystal polarized-neutron scattering experiments reveal persistence of highly structured magnetic diffuse and absence periodic order to T=0.05 K. employ reverse Monte Carlo refinements mean-field theory calculations construct an effective Hamiltonian which accounts for scattering. The interactions we identify describe emergent structure mimics triangular lattice antiferromagnet, one...
Abstract In this work we consider the geometrically exact shell model subjected to finite rotations, making use of rotation vector parameters for handling corresponding constrained smooth shells. A modification such a parameterization which is based on incremental and thus capable avoiding singularity problem also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Crystals are the elementary constituents of Laue lenses, an emerging technology which could allow realization a space-borne telescope 10–100 times more sensitive than existing ones, in 100 keV–1.5 MeV energy range. This paper addresses development efficient crystals for lens. In theoretical part, 35 candidate crystals, both pure and two-component considered. Their peak reflectivity at 100, 500 keV 1 is calculated assuming they mosaic crystals. It found that, by careful selection it possible...
We report resistivity measurements as a function of magnetic field or uniaxial stress across the martensitic transformation on Ni45Co5Mn37.5In12.5 Heusler single crystal. The and temperatures are strongly affected by application an consequent magnetoresistance piezoresistance that can reach up to 60% 122%, respectively, measured. This behavior opens large range possible applications with relatively small pressure control parameter tune resistivity.
Neutron backscattering spectroscopy with sub-μeV energy resolution has profited over recent years from intensity gains enabled by a phase space transformation (PST) chopper, which is fast-moving neutron optical component first proposed Schelten and Alefeld (Internal Report No. Jül1954, KFA Jülich, 1984). Here, we present its principle, the considerations for our technical layout, related challenges, mechanical aspects, tests to graphite mosaic crystals, moving center velocity of 243 m/s in...
Abstract A calorimetric investigation of a Ni 45 Co 5 Mn 37.5 In 12.5 single crystal has been carried out by combining differential scanning calorimetry (DSC) and heat capacity ( C ) measurements. The martensitic transition showing first-order character spread over wide temperature range, specific measuring technique T developed. This method—based on time-resolved analysis successive heating pulses—was found to yield an entropy change at the (Δ S tr that is very close derived from DSC. To...
We report on the first results obtained from our development project of focusing gamma-rays ($>$60 keV) by using Laue lenses. The lens prototype model has been assembled and tested. describe technique adopted capabilities at about 100 keV.
Results of reflectivity measurements mosaic crystal samples Cu (111) are reported. These tests were performed in the context a feasibility study hard X-ray focusing telescope for space astronomy with energy passband from 60 to 600 keV. The technique envisaged is that using crystals transmission configuration diffract X-rays Bragg diffraction (Laue lens). Laue lens assumed has spherical shape focal length $f$. It made flat tiles suitably positioned lens. grown and worked this project at...
In this last of a series three papers on the development an advanced solid-state neutron polarizer, we present final construction polarizer and results its commissioning. The uses spin-selective reflection neutrons by interfaces coated with polarizing super-mirrors. is built entirely in-house for PF1B cold beam facility at Institut Max von Laue–Paul Langevin (ILL). It has been installed in casemate tested under real conditions. average transmission “good” spin component measured to be...
By using differential scanning calorimetry, direct entropy variations have been recorded along the martensitic transformation of a Ni45.5Co4.5Mn37In13 single crystal in various magnetic fields. A large negative magnetocaloric effect associated to from virtually non-magnetic martensite ferromagnetic austenite coexists with weaker, positive related Curie transition latter phase. It is shown that field-dependence maximum isothermal change can be modelized by taking into account interplay both...
We report on the feasibility study of a Laue lens for hard X-rays (>60 keV)based mosaic crystals, astrophysical applications. In particular we discuss scientific motivations, its functioning principle, procedure followed to select suitable crystal materials, criteria adopted establish dimensions and their distribution in order obtain best focusing capabilities, optimizing effective area given passband. also effects misalignments tiles due unavoidable mechanical errors assembling lens. A...