Formation and dynamics of easy orientation axis in magnetic field on PVCN-F surface

2006 ◽  
Vol 14 (4) ◽  
Author(s):  
O. Buluy ◽  
Y. Reznikov ◽  
K. Slyusarenko ◽  
M. Nobili ◽  
V. Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Easy Axis ◽  
Partial Relaxation ◽  
Soft Surface ◽  
Orientation Axis ◽  
The Magnetic Field ◽  
Additional Assumptions

AbstractWe describe the experiments on a magnetically-induced drift of the easy axis on a soft surface of photoaligning material fluoro-polyvinyl-cinnamate. We found unexpected partial relaxation of the drift of the easy axis after switching the magnetic field off. This relaxation cannot be explained in a framework of the existing models and requires additional assumptions about the drift process. We propose a model that explains the experimental data suggesting elastic-like behaviour of the polymer fragments during the drift of the easy axis.

ELECTROMAGNETIC FIELDS IN AN N‐LAYER ANISOTROPIC HALF‐SPACE

Geophysics ◽  
1967 ◽  
Vol 32 (4) ◽  
pp. 668-677 ◽  
Author(s):  
Douglas P. O’Brien ◽  
H. F. Morrison
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Plane Wave ◽  
Half Space ◽  
Electric Fields ◽  
Field Measurements ◽  
Large Scatter ◽  
Tensor Impedance ◽  
The Magnetic Field ◽  
Made In

From Maxwell’s equations and Ohm’s law for a horizontally anisotropic medium, it may be shown that two independent plane wave modes propagate perpendicular to the plane of the anisotropy. Boundary conditions at the interfaces in an n‐layered model permit the calculation, through successive matrix multiplications, of the fields at the surface in terms of the fields propagated into the basal infinite half space. Specifying the magnetic field at the surface allows the calculation of the resultant electric fields, and the calculation of the entries of a tensor impedance relationship. These calculations have been programmed for the digital computer and an interpretation of impedances obtained from field measurements may thus be made in terms of the anisotropic layering. In addition, apparent resistivities in orthogonal directions have been calculated for specific models and compared to experimental data. It is apparent that the large scatter of observed resistivities can be caused by small changes in the polarization of the magnetic field.

Spin reorientation transition: phase diagrams and entropy change

2011 ◽  
Vol 1310 ◽  
Author(s):  
Vittorio Basso ◽  
Carlo P. Sasso ◽  
Michaela Kuepferling
Keyword(s):  
Magnetic Field ◽  
Easy Axis ◽  
Entropy Change ◽  
Rotating Magnetic Field ◽  
Spin Reorientation ◽  
Temperature Dependent ◽  
First Order ◽  
Crystalline Anisotropy ◽  
The Magnetic Field ◽  
Magneto Crystalline Anisotropy

ABSTRACTIn this paper we review the phase diagram and derive the entropy change for spin reorientation transitions by considering first order magnetization process theory with temperature dependent magneto-crystalline anisotropy constants. We derive the magnetic field-induced entropy change Δs for a transition between easy axis and easy plane, showing that for alternating magnetic field, Δs has a change of sign at the reorientation temperature, while for rotating magnetic field its sign is definite. We apply the model to CoZn W-type barium ferrite.

Metamagnetic Transitions and Stepwise GMR in Uniaxial Fe/Cr Superlattices

2006 ◽  
Vol 52 ◽  
pp. 104-109
Author(s):  
V.V. Ustinov ◽  
L.N. Romashev ◽  
M.A. Milyaev ◽  
T.P. Krinitsina ◽  
A.M. Burkhanov
Keyword(s):  
Magnetic Field ◽  
Comparative Analysis ◽  
Easy Axis ◽  
Magnetic Moments ◽  
Film Plane ◽  
Qualitative Information ◽  
Spin Flip ◽  
Plane Anisotropy ◽  
The Magnetic Field ◽  
Mgo Substrate

We investigated the structure, magnetic and magnetoresistive properties of antiferromagnetically coupled [Fe(85Å)/Cr(tCr)]12 superlattices with the Cr layers thickness tCr = 12.4 and 13.6 Å, grown simultaneously on (100)MgO and (211)MgO substrates. It is shown that the (211)MgO substrate is appropriate for the growth of (210)Fe/Cr multilayers with a strong uniaxial in-plane anisotropy. The stepwise behavior of magnetization and magnetoresistance is revealed in the case when the magnetic field is applied along the easy axis in a film plane of (211)MgO/[(210)Fe/Cr]12 superlattices. The steps on M(H) and ΔR(H)/R dependences are caused by the flip of the magnetic moments of individual Fe layers. The qualitative information about the sequence of spin-flip transitions is extracted from the comparative analysis of magnetization and magnetoresistance data.

scholarly journals Effect of a stochastic electric field on plasma confinement in FTU

2016 ◽  
Vol 31 (02) ◽  
pp. 1650005 ◽  
Author(s):  
Roberto Martorelli ◽  
Giovanni Montani ◽  
Nakia Carlevaro
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electric Field ◽  
Uniform Magnetic Field ◽  
Planck Equation ◽  
Plasma Confinement ◽  
Stochastic Field ◽  
Magnetically Confined ◽  
The Magnetic Field ◽  
Plasma Profile

We discuss a stochastic model for the behavior of electrons in a magnetically confined plasma having axial symmetry. The aim of the work is to provide an explanation for the density limit observed in the Frascati Tokamak Upgrade (FTU) machine. The dynamical framework deals with an electron embedded in a stationary and uniform magnetic field and affected by an orthogonal random electric field. The behavior of the average plasma profile is determined by the appropriate Fokker–Planck equation associated to the considered model and the disruptive effects of the stochastic electric field are shown. The comparison between the addressed model and the experimental data allows to fix the relevant spatial scale of such a stochastic field. It is found to be of the order of the Tokamak micro-physics scale, i.e. few millimeters. Moreover, it is clarified how the diffusion process outlines a dependence on the magnetic field as [Formula: see text].

Phonon properties of delafossite multiferroic compound CuFeO2. Comparison with CuCrO2

2019 ◽  
Vol 33 (12) ◽  
pp. 1950141
Author(s):  
A. T. Apostolov ◽  
I. N. Apostolova ◽  
J. M. Wesselinowa
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Phase Transition ◽  
Dopant Concentration ◽  
Phonon Energy ◽  
Function Technique ◽  
Ion Doping ◽  
Increasing Temperature ◽  
The Magnetic Field ◽  
Phonon Properties

The temperature, magnetic field and ion doping dependence of the phonon properties of CuFeO2 are studied on the basis of a microscopic model and using Green’s function technique. The phonon energy decreases with increasing temperature, whereas the phonon damping increases. There is a kink at the phase transition temperature [Formula: see text] which shows the influence of the magnetic field on the phonon properties. The kinks vanish by applying an external magnetic field. By doping of ions with different radius compared to the Fe ion, the phonon energy in CuFeO2 can increase (Ga) or decrease (Sc) with increasing dopant concentration, whereas the damping is always enhanced. The results are compared with those of CuCrO2. Some discrepancies in the literature are discussed. The observed results are in qualitative agreement with the experimental data.

Upper Critical Field and Irreversibility Line in Bi2Sr2CuO6+δ/CaCuO2 Superconducting Superlattices Obtained by MBE

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2767-2772
Author(s):  
Matteo Salvato ◽  
Carmine Attanasio ◽  
Gerardina Carbone ◽  
Rosalba Fittipaldi ◽  
Tiziana Di Luccio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thin Films ◽  
Phase Diagrams ◽  
Applied Magnetic Field ◽  
Three Dimensional ◽  
Upper Critical Field ◽  
Resistivity Measurements ◽  
T Phase ◽  
The Magnetic Field

Resistivity measurements in external applied magnetic field up to 8.5T have been performed on Bi2Sr2CuO6+δ/CaCuO2 superconducting superlattices obtained by MBE. The magnetic field (H) vs. temperature (T) phase diagrams have been determined and the experimental data have been compared with that obtained in the case of Bi2Sr2CuO6+δ thin films deposited with the same technique. A reduction of the anisotropy has been obtained in the case of the superlattices with respect to the case of Bi2Sr2CuO6+δ thin films and a three dimensional behavior has been observed by paraconductivity measurements.

INVESTIGATING THE TIME DEPENDENCE OF THE MR EFFECT

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4832-4840 ◽  
Author(s):  
FERNANDO D. GONCALVES ◽  
J. DAVID CARLSON
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Response Time ◽  
Time Dependence ◽  
Dwell Time ◽  
High Shear ◽  
Proposed Model ◽  
Mr Effect ◽  
The Magnetic Field ◽  
Field Strengths

Magnetorheological fluids are known to respond in a matter of milliseconds to the application of a magnetic field. To date, however, very little work has been done to study the time dependence of the MR response. The purpose of this study is to investigate the response time of the fluid. Experiments were conducted on a high shear rate rheometer capable of fluid speeds in excess of 35 m/s. With an MR valve length of 6.35 mm, the resulting dwell times were as low as 0.18 ms. For each of three magnetic field strengths, a reduction in yield stress is observed as dwell time decreases. A model is proposed to represent the time response of the fluid to the application of the magnetic field. The experimental data and the proposed model are used to identify the response time of the fluid for each field strength. Results indicate that as the magnetic field increases, the response time of the MR fluid decreases. For the range of magnetic field strengths considered in this study the response time of the fluid ranged from 0.24 ms to 0.19 ms.

scholarly journals MULTI-PURPOSE MODES OF FORMATION OF ELECTRON BEAMS IN THE CYLINDRICAL MAGNETIC FIELD OF THE MAGNETRON GUN

2021 ◽  
pp. 45-49
Author(s):  
A.S. Mazmanishvili ◽  
N.G. Reshetnyak
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electron Beam ◽  
Electron Beams ◽  
Electron Flow ◽  
Axial Direction ◽  
Beam Diameter ◽  
Transport Channel ◽  
Comparison Of The Results ◽  
The Magnetic Field

The results of the study on the formation of electron beams by the magnetron gun at various configurations of the magnetic field in the beam transport channel are presented. A technique for modeling the processes of formation of electron flows and control of the distribution of beams by collimation is presented. Numerical simulation of the dynamics of electron beams in the magnetic field of the gun for its various configurations has been carried out. Experimental data on the transportation and collimation of electron beams are presented. The possibility of stable formation of an electron beam in the axial direction during its transportation is shown. Imprints of the collimated electron beam were obtained on metal targets. The possibility of controlling the beam diameter by varying the magnetic field is shown. Comparison of the results of numerical modeling and experimental data on the motion and collimation of the tubular electron flow is carried out.

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