scholarly journals Analysis of the halo background in femtosecond slicing experiments

2016 ◽  
Vol 23 (3) ◽  
pp. 700-711 ◽  
Author(s):  
Daniel Schick ◽  
Loïc Le Guyader ◽  
Niko Pontius ◽  
Ilie Radu ◽  
Torsten Kachel ◽  
...  
Keyword(s):  
Magnetic Circular Dichroism ◽  
Analytical Models ◽  
Simplified Model ◽  
Experimental Characterization ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption ◽  
Physical Quantities

The slicing facility FemtoSpeX at BESSY II offers unique opportunities to study photo-induced dynamics on femtosecond time scales by means of X-ray magnetic circular dichroism, resonant and non-resonant X-ray diffraction, and X-ray absorption spectroscopy experiments in the soft X-ray regime. Besides femtosecond X-ray pulses, slicing sources inherently also produce a so-called `halo' background with a different time structure, polarization and pointing. Here a detailed experimental characterization of the halo radiation is presented, and a method is demonstrated for its correct and unambiguous removal from femtosecond time-resolved data using a special laser triggering scheme as well as analytical models. Examples are given for time-resolved measurements with corresponding halo correction, and errors of the relevant physical quantities caused by either neglecting or by applying a simplified model to describe this background are estimated.

Characterization of a prototype pixel array detector (PAD) for use in microsecond framing time-resolved X-ray diffraction studies

1997 ◽  
Vol 44 (3) ◽  
pp. 950-956 ◽  
Author(s):  
S.L. Barna ◽  
J.A. Shepherd ◽  
M.W. Tate ◽  
R.L. Wixted ◽  
E.F. Eikenberry ◽  
...  
Keyword(s):  
Array Detector ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Pixel Array ◽  
Pixel Array Detector

scholarly journals Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Daisuke Ogawa ◽  
Ryo Kitaura ◽  
Takeshi Saito ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Yield ◽  
Single Wall Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Wall Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Molecules ◽  
X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

X-ray absorption and magnetic circular dichroism characterization of a novel ferromagnetic MnNx phase in Mn/Si3N4 multilayers

2008 ◽  
Vol 93 (25) ◽  
pp. 252506 ◽  
Author(s):  
E. Céspedes ◽  
Y. Huttel ◽  
L. Martínez ◽  
A. de Andrés ◽  
J. Chaboy ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
X Ray ◽  
X Ray Absorption ◽  
Circular Dichroïsm

Ferromagnetic Ge1-xMx (M = Mn, Co, and Fe) Nanowires

2007 ◽  
Vol 1032 ◽  
Author(s):  
Yong Jae Cho ◽  
chang hyun Kim ◽  
jeunghee Park
Keyword(s):  
Magnetic Circular Dichroism ◽  
Room Temperature Ferromagnetism ◽  
Cluster Formation ◽  
Magnetization Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
X Ray Absorption ◽  
Mn Doped ◽  
Fe Ions

AbstractWe synthesized Ge and Ge1-xMx (M = Mn, Co, and Fe, x ≤ 0.2) nanowires using thermal vapour transport method. All nanowires consisted of single-crystalline Ge nanocrystals grown uniformly with the [111] direction. High-resolution X-ray diffraction pattern shows no cluster formation for all Ge1-xMx nanowires. The Mn and Fe doping decreases the lattice constant, but not Co doping. X-ray absorption spectroscopy and X-ray magnetic circular dichroism measurement revealed that the Mn2+ and Fe2+ ions preferentially occupy the tetrahedral sites, substituting for Ge. We suggest that the Mn or Fe ions produce dopant-acceptor hybridization with host defects in p-type Ge, but not Co ions. The magnetic moment of Mn2+ ions reaches a maximum for x = ∼ 0.1, which is much larger than that of the Fe2+ ions. The magnetization measurement also confirms the room-temperature ferromagnetism of Mn-doped Ge nanowires, which is maximized at x = ∼ 0.1. We conclude that the Mn ions are most efficiently doped into the Ge nanowires to form a ferromagnetic semiconductor.

Martensite Transition and Microscopic Magnetism of Epitaxial Ni2MnGa Films

2007 ◽  
Vol 1050 ◽  
Author(s):  
Gerhard Jakob ◽  
Tobias Eichhorn ◽  
Michael Kallmayer ◽  
Hans-Joachim Elmers
Keyword(s):  
Magnetic Circular Dichroism ◽  
Theoretical Calculations ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Absorption Feature ◽  
X Ray Diffraction ◽  
Orbital Contribution ◽  
X Ray ◽  
Transmission Geometry ◽  
X Ray Absorption

AbstractA magnetically induced shape memory effect in Ni2MnGa results in huge magnetostrictive effects of several percent. Using x-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD) we investigated element specific magnetic moments and electronic structure of single crystalline, (110) oriented Ni2MnGa films on a-plane Al2O3 substrates in the austenite and martensite state. The structural phase transition of the samples is evident from temperature dependent x-ray diffraction and magnetization measurements. The Ni XAS differ significantly for temperatures above and below the martensite transition in agreement with published ab-initio calculations. Using XAS in transmission geometry on our thin film samples we observe the corresponding reduction of the absorption feature as predicted by theoretical calculations. The XMCD analysis shows the orbital contribution of the Ni electrons to be responsible for the magnetic anisotropy.

On X-Ray Diffraction and X-Ray Absorption Spectroscopy Characterization of Ball Milled Iron Copper Solid Solution

1998 ◽  
Vol 269-272 ◽  
pp. 473-478 ◽  
Author(s):  
Francsco Cardellini ◽  
Vittoria Contini ◽  
Gregorio D'Agostino ◽  
Adriano Filipponi
Keyword(s):  
Solid Solution ◽  
Absorption Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Copper ◽  
X Ray Absorption

A dispenser–reactor apparatus applied forin situXAS monitoring of Pt nanoparticle formation

2015 ◽  
Vol 22 (3) ◽  
pp. 736-744 ◽  
Author(s):  
Jocenir Boita ◽  
Marcus Vinicius Castegnaro ◽  
Maria do Carmo Martins Alves ◽  
Jonder Morais
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Pt Nanoparticles ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Two Stages ◽  
X Ray Absorption

In situtime-resolved X-ray absorption spectroscopy (XAS) measurements collected at the PtL3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser–reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.

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