Search results for "spin polarization"
showing 10 items of 182 documents
Certain doping concentrations caused half-metallic graphene
2017
This work is supported by National Natural Science Foundation of China (Grant No. 21173096).
Bulk spin polarization of magnetite from spin-resolved hard x-ray photoelectron spectroscopy
2021
Physical review / B 104(4), 045129 (1-10) (2021). doi:10.1103/PhysRevB.104.045129
Accurate Prediction of Hyperfine Coupling Tensors for Main Group Elements Using a Unitary Group Based Rigorously Spin-Adapted Coupled-Cluster Theory
2019
We present the development of a perturbative triples correction scheme for the previously reported unitary group based spin-adapted combinatoric open-shell coupled-cluster (CC) singles and doubles (COS-CCSD) approach and report on the applications of the newly developed method, termed "COS-CCSD(T)", to the calculation of hyperfine coupling (HFC) tensors for radicals consisting of hydrogen, second- and third-row elements. The COS-CCSD(T) method involves a single noniterative step with [Formula: see text] scaling of the computational cost for the calculation of triples corrections to the energy. The key feature of this development is the use of spatial semicanonical orbitals generated from st…
Nuclear hyperpolarization of 3He by magnetized plasmas
2018
International audience; We describe a method, referred to as PAMP (polarization of atoms in a magnetized plasma), that allowshyperpolarization of 3He nuclear spins at high magnetic field solely by excitation of a rf gas discharge.A magnetized plasma is obtained when the mean free path of the free electrons is much larger than theirgyration radius in the rf gas discharge. Investigations of PAMP are carried out in the 1–15-mbar pressure rangewith rf excitation around 100 MHz. Quantitative NMR measurements at 4.7 T and room temperature showthat, for different cell sizes and gas densities, 3He nuclear polarizations in the 1 to 9% range are achieved(i.e., larger than the Boltzmann equilibrium sp…
Spin Heat Engine Coupled to a Harmonic-Oscillator Flywheel
2018
We realize a heat engine using a single electron spin as a working medium. The spin pertains to the valence electron of a trapped $^{40}$Ca$^+$ ion, and heat reservoirs are emulated by controlling the spin polarization via optical pumping. The engine is coupled to the ion's harmonic-oscillator degree of freedom via spin-dependent optical forces. The oscillator stores the work produced by the heat engine and therefore acts as a flywheel. We characterize the state of the flywheel by reconstructing the Husimi $\mathcal{Q}$ function of the oscillator after different engine runtimes. This allows us to infer both the deposited energy and the corresponding fluctuations throughout the onset of oper…
Ferromagnetic Coupling through Spin Polarization in a Dinuclear Copper(II) Metallacyclophane.
2001
[DT] Von organischen Radikalen zu Metallkomplexen konnte das bekannte Konzept für Ferroelektrika erfolgreich ausgedehnt werden: Die Abbildung zeigt ein Cyclophan-artiges Molekül mit einem Triplett-Grundzustand, in dem zwei CuII-Zentren von einem doppelten m-Phenylendiamid-Gerüst zusammengehalten werden.
Topology and Spin Polarization in Sheetlike Metal(II) Polymers: [ML2X2] (M ˭ Mn, Fe, Co or Ni, L = Pyrimidine or Pyrazine and X = NCS or NCO)
1999
The preparation and the structural and magnetic characterization of a series of sheetlike transition metal polymers of formula [ML2X2] [M ˭ Mn(II), Fe(II), Co(II) and Ni(II): L = pyrazine (pyz) and...
Transmission of electrons through ferromagnetic material and applications to detection of electron spin polarization
1993
The salient features of the total low energy inelastic electron scattering cross section in transition metals are described by a constant term σ 0 plus a term σ d that is proportional to the number of unoccupied d-orbitals. This simple model predicts that low energy electrons transmitted through a ferromagnetic ultrathin film acquire a transport spin polarization a(x). Using the ratio σ 0 /σ d as the only adjustable parameter, the model predicts the enhancement of the spin polarization of the low energy cascade electrons as well as a(x) in reasonable agreement with the existing observations on Fe, Co and Ni. A detector for electron spin polarization P based on the spin dependent transmissio…
Magnetic tunneling junctions with the Heusler compound
2005
Abstract Certain Heusler phases belong to the materials which are discussed as potential half metals. Here, results of tunneling experiments with the full-Heusler alloy Co 2 Cr 0.6 Fe 0.4 Al are presented. The Heusler alloy is used as an electrode of magnetic tunneling junctions. The junctions are deposited by magnetron DC sputtering using shadow mask techniques with AlO x as a barrier and cobalt as counter electrode. Measurements of the magnetoresistive differential conductivity in a temperature range between 4 and 300 K are shown. An analysis of the barrier properties applying the Simmons model to the bias dependent junction conductivity is performed. VSM measurements were carried out to …
Interdisciplinary experiments with polarized 3He
1998
Abstract Optical pumping of metastable 3 He atoms is a very efficient method to produce large quantities of nuclear spin-polarized 3 He. Recent developments in mechanical compression of the gas, its storage and transport allow for its flexible use in different fields of physics and applied science. Among these are (1) scattering experiments of polarized beams from polarized 3 He-targets, (2) 3 He as neutron spin filter to polarize neutron beams at research reactors, and (3) polarized 3 He gas inhaled into the lungs to perform magnetic resonance imaging. The paper discusses the different topics along with results obtained in a first round of experiments.