Search results for "Magnetostatics"
showing 10 items of 28 documents
Reorientations and translations in a fragile glass-former: magnetic resonance studies of meta-fluoroaniline
1999
Abstract The rotational dynamics in supercooled liquid and glassy meta-fluoroaniline was studied using proton and fluorine spin-lattice relaxation times. It is shown that while proton relaxation is dominated by homonuclear relaxation, for fluorine heteronuclear relaxation prevails. The results could be well described using a distribution of correlation times. The mean correlation times show pronounced deviations from the simple Arrhenius law. In addition translational self-diffusion coefficients were measured for T>200 K using a static magnetic field gradient technique.
Coherent Manipulation of Polarization in Mixed-Valence Compounds by Electric Pulse via Landau–Zener Transitions
2012
In this contribution, we predict and theoretically investigate the effects of the electric field pulse in mixed valence (MV) dimers. These systems exhibit bistability with a large internal dipole moment mediated by the itinerant electron trapped by the vibronic coupling. In this sense, they are similar to single molecular magnets (SMMs) that are bistable systems possessing large long-living magnetization and exhibiting Landau−Zener (LZ) transitions. We propose a scheme for a controllable LZ tunnelling in MV systems that provides also a possibility to control the dipole moment of a dimeric MV unit. It is supposed that the static electric field initially polarizes the system, and then the uni…
Static magnetic field influence on rat brain function detected by heart rate monitoring.
2004
The aim of the present study was to identify the effects of a static magnetic field (SMF) on rat brain structures that control autonomic functions, specifically heart rate and heart rhythmicity. The experiments were carried out on 44 male Wistar rats under ketamine-xylazine anesthesia. SMF was induced using samarium-cobalt fused magnets (20 x 20 x 10 mm in size) placed bitemporally. Magnetic induction intensity was 100 mT on the surface of the head. Duration of magnetic field application was 15 min. An electrocardiogram was recorded from limb lead II, and both heart rate (average duration of cardiac cycles) and heart rhythmicity were analyzed before and after SMF application. SMF evoked cha…
Magnetic field-induced alignment of molecular rotor-shaped cyclophanes
2010
Molecular pinwheels consisting of dipolar substituted cyclophanes in solution can function as free microscopic rotors in the presence of a homogeneous static magnetic field B and a circularly polarized electric field E rotating on a plane containing B. Owing to the high magnetic anisotropy of [26](1,2,3,4,5,6)cyclophane and [36](1,2,3,4,5,6)cyclophane biased by strong ring currents, ∼1 in 105 molecules are expected to align with the C6 symmetry axis perpendicular to a magnetic field of 21 T. The magnetic-field-controlled alignment of rotor-shaped cyclophanes is insignificantly affected by nonpolar solvents, for example, toluene.
Laser Assisted Dirac Electron in a Magnetized Annulus
2021
We study the behaviour of a charge bound on a graphene annulus under the assumption that the particle can be treated as a massless Dirac electron. The eigenstates and relative energy are found in closed analytical form. Subsequently, we consider a large annulus with radius ρ∈[5000,10,000]a0 in the presence of a static magnetic field orthogonal to its plane and again the eigenstates and eigenenergies of the Dirac electron are found in both analytical and numerical form. The possibility of designing filiform currents by controlling the orbital angular momentum and the magnetic field is shown. The currents can be of interest in optoelectronic devices that are controlled by electromagnetic radi…
Microwave harmonic emission in MgB2 superconductor: Comparison with YBA2CU3O7
2006
We report results of microwave second-harmonic generation in ceramic samples of MgB2, prepared by different methods. The SH signal has been investigated as a function of the temperature and the static magnetic field. The results are discussed in the framework of models reported in the literature. We show that the peculiarities of the SH signal are related to the specific properties of the sample. A comparison with the results obtained in ceramic and crystalline YBa2Cu3O7 shows that the second-harmonic emission in MgB2 is weaker than that observed in ceramic YBa2CuO7. (c) 2006 Wiley Periodicals, Inc.
Thermoelectric effects on electrically conducting particles in liquid metal
2015
International audience; The present paper deals with the thermoelectric effect on a solid electrically conducting particle immersed in a liquid metal under a temperature gradient. Superimposition of a static magnetic field induces thermoelectric magnetic (TEM) forces both in the solid and in the liquid. Considering a simple spherical particle, the electric current density and the corresponding forces can be calculated analytically. Two cases are considered according to the orientation of the magnetic field with respect to the temperature gradient. The corresponding flow fields around the particle are calculated in both cases. Grain motion is analyzed in the light of in-situ experiments perf…
<title>Influence of strong static magnetic field on human cancer HT 1080 cells</title>
2001
The aim of this study was to investigate strong uniform magnetic field influence on the human cancer cells HT 1080. The cells were treated with magnetic field of intensity 1,16 Tesla and with anticancer agent - cis-platinum 0.025 mg/ml or vincristinum 2-3 ng/ml. The intact and the treated cell samples were incubated in a medium with acridine orange (AO). The magnetic field after 15 minutes of influence significantly increased cytoplasmic red fluorescence. Increased AO accumulation in lysosomes suggested to cancer cell metabolic activity stimulation.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Modulating the polarization of broadband terahertz pulses from a spintronic emitter at rates up to 10 kHz
2021
Reliable modulation of terahertz electromagnetic waveforms is important for many applications. Here, we rapidly modulate the direction of the electric field of linearly polarized terahertz electromagnetic pulses with 1–30 THz bandwidth by applying time-dependent magnetic fields to a spintronic terahertz emitter. Polarity modulation of the terahertz field with more than 99% contrast at a rate of 10 kHz is achieved using a harmonic magnetic field. By adding a static magnetic field, we modulate the direction of the terahertz field between angles of, for instance, −53° and 53° at kilohertz rates. We believe our approach makes spintronic terahertz emitters a promising source for low-noise modula…
Multipactor Effect in a Parallel-Plate Waveguide Partially Filled With Magnetized Ferrite
2014
The aim of this paper is the analysis of the multipactor effect in a parallel-plate waveguide when a ferrite slab, transversally magnetized by a static magnetic field parallel to the waveguide walls, is present. Employing an in-house developed code, numerical simulations are performed to predict the multipactor radio frequency voltage threshold in such a ferrite-loaded waveguide. Variations of the ferrite magnetization field strength and the ferrite slab height are analyzed. Effective electron trajectories are also shown for a better understanding of the breakdown phenomenon, finding different multipactor regimes.