Search results for " electrons"
showing 10 items of 1168 documents
Zur Sekund�relektronenemission durch Argonionen und Argonatome im Energiebereich von 1 bis 20 keV
1966
Be-, CuBe-, Cu- and Al-targets are bombarded by single A+ and A0 in the energy range from 1 to 20 keV. The secondary electrons accelerated by 20 keV are counted by a proportional counter backed by a multichannel analyser. The probability distributionPn of emission ofn=0,1, 2, 3, ... secondary electrons can be found from the pulse height distribution. WhenPn is known the yield for A+ and A0 can be calculated. The counting of neutrals in the energy range investigated is discussed.
Nuclear magnetic resonance at millitesla fields using a zero-field spectrometer
2016
We describe new analytical capabilities for nuclear magnetic resonance (NMR) experiments in which signal detection is performed with chemical resolution (via spin-spin J couplings) in the zero to ultra-low magnetic field region, below 1μT. Using magnetic fields in the 100μT to 1mT range, we demonstrate the implementation of conventional NMR pulse sequences with spin-species selectivity.
The large-area micro-channel plate entrance detector of the heavy-ion magnetic spectrometer PRISMA
2005
This paper describes the entrance detector of the magnetic spectrometer PRISMA recently installed at Legnaro. The detector is based on rectangular (80 x 100 mm(2)) Micro-Channel Plates (MCP). It provides a fast time signal and its position-sensitive anode allows to extract the X and Y information. It exploits an electrostatic field for the acceleration of secondary electrons from a thin Carbon foil (similar or equal to 20 mu g/cm(2)) onto the MCP assembly. The electrons are guided by a parallel magnetic field. Good performances were obtained in the laboratory tests. The detector is presently installed at the entrance of PRISMA and gives resolutions <= 400 ps in time, and 1 mm in both X and …
High spin states of120Ba
1991
The very neutron deficient nucleus120Ba has been investigated in a high-spin γ-spectroscopic study. The yrast band of120Ba is extended up to spin 22ħ and one tentatively assigned negative-parity side band is observed up to spin 15ħ. The experimental results are compared with Total Routhian Surface calculations.
Spinrotator for MAMI
1991
A source of polarized electrons based on the photoemission of a GaAsP-cathode [1] has been set up to inject polarized electrons in the Mainz microtron MAMI. In order to compensate the spin precession in MAMI a spinrotator system has to be integrated in the 100 keV beamline from the source to the injector linac to achieve the required longitudinal spin direction at target position.
Tensor Network Annealing Algorithm for Two-Dimensional Thermal States
2019
Tensor network methods have become a powerful class of tools to capture strongly correlated matter, but methods to capture the experimentally ubiquitous family of models at finite temperature beyond one spatial dimension are largely lacking. We introduce a tensor network algorithm able to simulate thermal states of two-dimensional quantum lattice systems in the thermodynamic limit. The method develops instances of projected entangled pair states and projected entangled pair operators for this purpose. It is the key feature of this algorithm to resemble the cooling down of the system from an infinite temperature state until it reaches the desired finite-temperature regime. As a benchmark we …
Small-polaron transport inLa0.67Ca0.33MnO3thin films
1998
We present a detailed study of the activated resistivity of ${\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ films up to 600 K under the influence of high magnetic fields. Data in zero field can be explained by small polaron hopping as treated in the Friedman-Holstein theory. Based on the spin orientation of ferromagnetic clusters in a magnetic field, we develop a phenomenological model describing the temperature and field dependence of the resistivity with a minimum of free parameters. We find that the polarons have a magnetic contribution to their activation energy for hopping which depends on the variation of the spin order with increasing temperature and can be modified by a…
Discovery of a Transition to Global Spin-up in EXO 2030+375
2005
EXO 2030+375, a 42-second transient X-ray pulsar with a Be star companion, has been observed to undergo an outburst at nearly every periastron passage for the last 13.5 years. From 1994 through 2002, the global trend in the pulsar spin frequency was spin-down. Using RXTE data from 2003 September, we have observed a transition to global spin-up in EXO 2030+375. Although the spin frequency observations are sparse, the relative spin-up between 2002 June and 2003 September observations, along with an overall brightening of the outbursts since mid 2002 observed with the RXTE ASM, accompanied by an increase in density of the Be disk, indicated by infrared magnitudes, suggest that the pattern obse…
Theoretical study of resonant x-ray emission spectroscopy of Mn films on Ag.
2006
We report a theoretical study on resonant x-ray emission spectra (RXES) in the whole energy region of the Mn $L_{2,3}$ white lines for three prototypical Mn/Ag(001) systems: (i) a Mn impurity in Ag, (ii) an adsorbed Mn monolayer on Ag, and (iii) a thick Mn film. The calculated RXES spectra depend strongly on the excitation energy. At $L_3$ excitation, the spectra of all three systems are dominated by the elastic peak. For excitation energies around $L_2$, and between $L_3$ and $L_2$, however, most of the spectral weight comes from inelastic x-ray scattering. The line shape of these inelastic ``satellite'' structures changes considerably between the three considered Mn/Ag systems, a fact tha…
Thermal disorder driven magnetic phases in van der Waals magnet CrI3
2020
Abstract Magnetic phase transitions often occur spontaneously at specific critical temperatures and are instrumental to understand the origin of long-range spin order in condensed matter systems. The presence of more than one critical temperature (Tc) has been observed in several compounds where the coexistence of competing magnetic orders highlights the importance of phase separation driven by different factors such as pressure, temperature and chemical composition. However, it is unknown whether recently discovered two-dimensional (2D) van der Walls (vdW) magnetic materials show such intriguing phenomena that can result in rich phase diagrams with novel magnetic features to be explored. H…