Frequency Dependence of the Absorption Component of the Magnetic Susceptibility in Superconducting Y1Ba2Cu3O7

1987 ◽  
Vol 99 ◽  
Author(s):  
S. Ducharme ◽  
R. Durny ◽  
J. Hautala ◽  
O. G. Symko ◽  
P. C. Taylor ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Zero Magnetic Field ◽  
Square Root ◽  
Superconducting Transition ◽  
Absorption Component ◽  
Wide Range ◽  
Field Dependent ◽  
Dependent Absorption ◽  
Bulk Behavior

ABSTRACTWe report measurements of an apparent magnetic-field-dependent absorption (imaginary part of the a.c. magnetic susceptibility) in superconducting Y1Ba2Cu3O7 ceramics and crystals. The absorption, which is observed over a wide range of frequencies but only when the material is below the superconducting transition temperature, is characterized by a narrow (∼ 30 Gauss FWHM at 6 MHz) peak and a wide (> 10 kG) feature, both of which are maximum at zero magnetic field. The absorption strength varies approximately as one over the square root of the frequency. The unusual magnetic-field-dependent peaks in the magnetic susceptibility are inherent in single grains and therefore do not originate from intergrain Josephson currents or multigrain (i.e., percolative) loops. The susceptibility peaks must be due to bulk behavior, interactons at grain surfaces, intragrain current loops, or intra-grain Josephson Junctions.

Absorption Component of the Magnetic Susceptibility in Superconducting YBa2Cu3O7

1987 ◽  
Vol 99 ◽  
Author(s):  
R. Durny ◽  
S. Ducharme ◽  
J. Hautala ◽  
O. G. Symko ◽  
P. C. Taylor ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Characteristic Temperature ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Dc Voltage ◽  
Absorption Component ◽  
Field Dependent ◽  
Absorption Measurements

ABSTRACTMicrowave absorption measurements from 20 to 80 K in magnetic fields up to 12 kG are reported. Below a certain characteristic temperature T* = 80 ± 2 K < Tc the absorption in magnetic-field-cooled samples is smaller and broader in comparison to the zero-field-cooled samples. The incident microwave radiation induces a dc voltage across the sample which is also magnetic field dependent and peaks at zero magnetic field.

Scaling of Resistivities in MgB2

2006 ◽  
Vol 47 ◽  
pp. 113-117
Author(s):  
Petr Vašek
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Critical Temperature ◽  
External Magnetic Field ◽  
Transport Current ◽  
Zero Magnetic Field ◽  
Superconducting Transition ◽  
Hall Voltage ◽  
Transition Range ◽  
Width Of Superconducting Transition

Longitudinal and transverse voltages have been measured on thin films of MgB2 with different width of superconducting transition range. The study has been performed in zero and nonzero external magnetic fields. The non-zero transverse voltage has been observed in close vicinity of the critical temperature in zero external magnetic field while far enough from Tc this voltage has been zero. In magnetic field it merges into transverse voltage which is an even function with respect to the direction of the field. Usual Hall voltage starts to appear with increasing magnetic field. At the highest field the even voltage disappears and only the Hall voltage is measurable i.e. the transverse even voltage is suppressed with increasing magnetic field and increasing transport current as well. New scaling between transverse and longitudinal resistivities has been observed in the form ρxy~dρxx/dT . This correlation is valid not only in the zero magnetic field but also in nonzero magnetic field where transverse even voltage can be detected. Several models trying to explain observed results are discussed. The most promising seems to be guided motion of the vortices.

IMPACT OF NANO-Mo ADDITION/SUBSTITUTION ON THE PHASE FORMATION AND SUPERCONDUCTIVITY OF Mg1-xMoxB2 (x=0.0to 0.50)

2007 ◽  
Vol 21 (14) ◽  
pp. 875-883 ◽  
Author(s):  
MONIKA MUDGEL ◽  
V. P. S. AWANA ◽  
H. KISHAN ◽  
RAJEEV RAWAT ◽  
A. V. NARLIKAR ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Ambient Pressure ◽  
Upper Critical Field ◽  
Zero Field ◽  
Superconducting Transition ◽  
Irreversibility Field ◽  
Sharp Transition ◽  
Mo Content ◽  
Applied Fields

Bulk polycrystalline samples of nano- Mo doped MgB 2 were synthesized by Fe tube encapsulation at ambient pressure under argon annealing (850°C). Mo substitution takes place successfully at the Mg site in Mg 1-x Mo x B 2 only till x=0.2. For higher (x>0.2) Mo content the same did not enter the MgB 2 lattice but rather forms an isomorphic lattice in the host with decreased c but an increased a-parameter. The ρ(T) measurements showed superconducting transition temperature (T c ) of around 36 K for all the samples till x=0.3 and slightly decreased values of 35 and 34 K for x=0.4 and 0.5 samples, respectively. Resistivity under magnetic field [R(T)H] experiments showed distinct single peaks in dρ/dT for all applied fields up to 8 Tesla. The estimated upper critical field H c2 is 8 Tesla for pristine and x=0.2 samples at 15.6 and 19 K, respectively. Thus H c2 increases up to x=0.20 samples and decreases afterwards. Magnetic susceptibility measurements exhibited sharp transition to superconducting state with a sizeable diamagnetic signal at 38 K (T c ) in zero field-cooled measurements. Commendable current density (J c ) of up to 105 A/cm2 in 1–2 T (Tesla) fields at temperatures (T) of up to 10 K is seen from magnetization measurements invoking the Bean's critical state model for pristine samples. For higher fields above 2.5 Tesla the J c (H) characteristics of x=0.1 and 0.2 samples were found to be slightly superior to that for pristine samples with enhanced H irr (irreversibility field).

scholarly journals Study of magnetic field dependent viscosity on a soret driven ferrothermohaline convection in a rotating porous medium

2014 ◽  
Vol 19 (1) ◽  
pp. 61-77
Author(s):  
R. Hemalatha
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Taylor Number ◽  
Thermohaline Convection ◽  
Wide Range ◽  
Field Dependent ◽  
Magnetic Field Dependent Viscosity ◽  
Dependent Viscosity ◽  
The Magnetic Field ◽  
Oscillatory Instabilities

Abstract The effect of a magnetic field dependent viscosity on a Soret driven ferro thermohaline convection in a rotating porous medium has been investigated using the linear stability analysis. The normal mode technique is applied. A wide range of values of the Soret parameter, magnetization parameter, the magnetic field dependent viscosity, Taylor number and the permeability of porous medium have been considered. A Brinkman model is used. Both stationary and oscillatory instabilities have been obtained. It is found that the system stabilizes only through oscillatory mode of instability. It is found that the magnetization parameter and the permeability of the porous medium destabilize the system and the Soret parameter, the magnetic field dependent viscosity and the Taylor number tend to stabilize the system. The results are presented numerically and graphically

scholarly journals A method of measuring magnetic susceptibilities

1931 ◽  
Vol 132 (820) ◽  
pp. 442-459 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Torsion Balance ◽  
The Body ◽  
Small Element ◽  
Uniform Field ◽  
Magnetic Susceptibilities ◽  
Wide Range ◽  
Faraday Method ◽  
The Magnetic Field

Among the different methods which can be used to measure the magnetic susceptibility of feebly magnetic substances, the most practical, and those most frequently employed at the present time, depend essentially on the measurement of the force acting on the substance when placed in a non-uniform field. This force is given by the well-known formula F x = χ ∫ v 0 H d H/d x d V, where χ is the volume susceptibility, (H) is the magnetic field, d H/ d x is the gradient of the magnetic field in the direction x in which the force is measured at the site of a small element of volume ( d V). Corresponding to the wide range of susceptibility, and to the different physical states and conditions which occur, a number of methods of measuring this force have been developed. In all these methods, since they are based on the measurement of the force on the substance, and since it is by the displacement of the body that the force is measured, it is essential that the body should be movable. The force acting on the body is small, usually only a few dynes, and delicate methods have to be used for making the measurements, as, for instance, in the Curie-Faraday method where the substance is carried on a sensitive torsion balance.

scholarly journals Introduction to Quantitative Susceptibility Mapping and Susceptibility Weighted Imaging

2019 ◽  
Vol 92 (1101) ◽  
pp. 20181016 ◽  
Author(s):  
Pascal P. R. Ruetten ◽  
Jonathan H. Gillard ◽  
Martin J. Graves
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
External Magnetic Field ◽  
Clinical Applications ◽  
Susceptibility Mapping ◽  
Susceptibility Weighted Imaging ◽  
Post Processing ◽  
Quantitative Susceptibility Mapping ◽  
Wide Range

Quantitative Susceptibility Mapping (QSM) and Susceptibility Weighted Imaging (SWI) are MRI techniques that measure and display differences in the magnetization that is induced in tissues, i.e. their magnetic susceptibility, when placed in the strong external magnetic field of an MRI system. SWI produces images in which the contrast is heavily weighted by the intrinsic tissue magnetic susceptibility. It has been applied in a wide range of clinical applications. QSM is a further advancement of this technique that requires sophisticated post-processing in order to provide quantitative maps of tissue susceptibility. This review explains the steps involved in both SWI and QSM as well as describing some of their uses in both clinical and research applications.

Effect of magnetic field dependent viscosity on Soret-driven ferrothermohaline convection saturating an anisotropic porous medium of sparse particle suspension

2014 ◽  
Vol 11 (3) ◽  
pp. 213-228 ◽  
Author(s):  
R. Sekar ◽  
K. Raju
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Soret Effect ◽  
Anisotropy Ratio ◽  
Free Boundaries ◽  
Wide Range ◽  
Field Dependent ◽  
Anisotropic Porous Medium ◽  
Mfd Viscosity ◽  
Dependent Viscosity

Thermoconvective instability with Soret effect in multi-component fluids has wide range of applications in heat and mass transfer. This work deals with the theoretical investigation of the effect of magnetic field dependent (MFD) viscosity on Soret-driven ferrothermohaline convection heated and salted from below in an anisotropic porous medium subjected to a transverse uniform magnetic field. The resulting eigen value problem is solved using Brinkman model. An exact solution is obtained for the case of two free boundaries and the stationary and oscillatory instabilities are investigated by using linear stability analysis and normal mode technique for the vertical of anisotropic porous medium. The analysis has been made for different parameters like porosity, anisotropy, ratio of heat transport to mass transport, buoyancy magnetization, non-buoyancy magnetization, Soret parameter and Salinity Rayleigh number. The effect of MFD viscosity is assumed to be isotropy. It is found that the presence of MFD viscosity has a stabilizing effect, whereas magnetization has a destabilizing effect.

Peculiarities of the Resistive State in Mo/Si Superlattices in a Magnetic Field

2003 ◽  
Vol 17 (10n12) ◽  
pp. 627-634 ◽  
Author(s):  
A. Yu. Aladyshkin ◽  
A. Yu. Klimov ◽  
M. A. Kucherenko ◽  
V. V. Kurin ◽  
V. L. Mironov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Transport Properties ◽  
Transverse Magnetic ◽  
Zero Magnetic Field ◽  
Experimental Investigations ◽  
Resistive State ◽  
Sharp Change ◽  
Superconducting Transition ◽  
Multilayered Structures

The experimental investigations of the transport properties of the superconducting Mo/Si multilayered structures are presented. The observed anisotropy of the electrical resistivity of Mo/Si bridges in a weak magnetic fields H ≲ 5 × 102 Oe is in agreement with the data reported earlier. However, for the Mo/Si microbridges with the width 2 μm in a transverse magnetic field H ≳ 5 × 102 Oe we have found out that the temperature dependence of the in-plane resistivity R(T) demonstrates a sharp change of the resistivity at a certain critical temperature T* < Tc, where Tc is the superconducting transition temperature in a zero magnetic field. For a parallel magnetic field this step-like behavior has not been revealed; we neither observed this effect in wider bridges. The comparison of the transport properties and the nonlinear microwave characteristics is presented. A possible origin of this unusual temperature dependence of R(T) is proposed.

Oxygen Separation/Enrichment From Atmospheric Air Using Magnetizing Force: Air Flow in a Duct Under Magnetic Field Gradient

Materials ◽  
2005 ◽  
Author(s):  
Yutaka Asako ◽  
Yohei Suzuki
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Field Gradient ◽  
Strong Magnetic Field ◽  
Magnetic Field Gradient ◽  
Air Flow ◽  
Oxygen Separation ◽  
Atmospheric Air ◽  
Wide Range ◽  
Magnetizing Force

Oxygen is paramagnetic gas and it has relatively high magnetic susceptibility. On the contrary, nitrogen is diamagnetic gas and it has relatively low and negative magnetic susceptibility. This results in counter magnetizing forces acting on these gases. The possibility of oxygen separation/enrichment from atmospheric air flow using a magnetizing force was investigated numerically. Direct Simulation Monte Carlo (DSMC) method was utilized to obtain distribution of oxygen concentration of air flow in a parallel-plate duct under a strong magnetic field gradient. The molecular movement was calculated by taking into account the magnetizing forces on the molecules. The computations were performed for a wide range of pressure and magnetic flux density gradient. The simulation results showed that there is a possibility of oxygen separation/enrichment from decompressed air under a strong magnetic field gradient.

scholarly journals Chiral plasmons without magnetic field

2016 ◽  
Vol 113 (17) ◽  
pp. 4658-4663 ◽  
Author(s):  
Justin C. W. Song ◽  
Mark S. Rudner
Keyword(s):  
Magnetic Field ◽  
Zero Magnetic Field ◽  
Emergent Properties ◽  
Edge States ◽  
Optically Pumped ◽  
New Class ◽  
Wide Range ◽  
Dirac Materials ◽  
Interacting Electrons ◽  
Collective Oscillations

Plasmons, the collective oscillations of interacting electrons, possess emergent properties that dramatically alter the optical response of metals. We predict the existence of a new class of plasmons—chiral Berry plasmons (CBPs)—for a wide range of 2D metallic systems including gapped Dirac materials. As we show, in these materials the interplay between Berry curvature and electron–electron interactions yields chiral plasmonic modes at zero magnetic field. The CBP modes are confined to system boundaries, even in the absence of topological edge states, with chirality manifested in split energy dispersions for oppositely directed plasmon waves. We unveil a rich CBP phenomenology and propose setups for realizing them, including in anomalous Hall metals and optically pumped 2D Dirac materials. Realization of CBPs will offer a powerful paradigm for magnetic field-free, subwavelength optical nonreciprocity, in the mid-IR to terahertz range, with tunable splittings as large as tens of THz, as well as sensitive all-optical diagnostics of topological bands.

Sign in / Sign up

Export Citation Format

Share Document