Critical temperature of the superconducting transition of individual phases of multiphase bismuth cuprates after cooling in a magnetic field to a temperature of 77 K

2019 ◽  
Vol 45 (4) ◽  
pp. 386-394
Author(s):  
J. G. Chigvinadze ◽  
S. M. Ashimov ◽  
J. V. Acrivos ◽  
D. D. Gulamova
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Superconducting Transition ◽  
Bismuth Cuprates

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.

scholarly journals Размерные зависимости магнитных свойств сверхпроводящих наноструктур свинца в пористом стекле

2018 ◽  
Vol 60 (6) ◽  
pp. 1058
Author(s):  
Н.Ю. Михайлин ◽  
Д.В. Шамшур ◽  
Р.В. Парфеньев ◽  
В.И. Козуб ◽  
Ю.М. Гальперин ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Low Temperature ◽  
Porous Glass ◽  
Magnetic Moment ◽  
Glass Matrix ◽  
Critical Magnetic Field ◽  
Superconducting Transition ◽  
Qualitative Model ◽  
Flux Jumps

AbstractSuperconducting structures Pb–PG formed by filling a porous glass matrix with the lead from melt under pressure have been investigated. Samples with characteristic pore structure diameters of d ≈ 7, 3, and 2 nm have been studied. It has been found that the critical temperature of the superconducting transition in the samples under study is similar to the corresponding value T _ c ≈ 7.2 K for bulk lead. At the same time, it has been observed that the critical magnetic field of the nanocomposites, which attains H _ c ( T = 0 K) ≈ 165 kOe for Pb–PG (3 nm), exceeds several times the value H _ c (0) = 803 Oe for bulk lead. The low-temperature magnetic- field dependences of magnetic moment M ( H ) contain quasi-periodic flux jumps, which vanish with a decrease in the lead nanostructure diameter. A qualitative model of the observed effects is considered.

Thermodynamic properties of charged ideal spin-1 bosons in a trap under a magnetic field

2014 ◽  
Vol 28 (26) ◽  
pp. 1450206 ◽  
Author(s):  
Yushan Li
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
External Magnetic Field ◽  
Thermodynamic Properties ◽  
Bose Gases ◽  
Spin Factor ◽  
Classical Approximation ◽  
Spinless Case

Thermodynamics of trapped charged ideal spin-1 bosons confined in a magnetic field are investigated within semi-classical approximation and truncated-summation approach. It is shown that the critical temperature increases slightly at the first, and then decreases slowly with increasing external magnetic field. Charged spin-1 Bose gases present a crossover from diamagnetism to paramagnetism as the spin factor increases. Charged spin-1 Bose gases exhibit distinct thermodynamic behaviors from the spinless case.

CRITICAL FIELD AND MAGNETORESISTANCE OF SINGLE CRYSTAL TmNi2B2C

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3715-3717 ◽  
Author(s):  
D. G. NAUGLE ◽  
K. D. D. RATHNAYAKA ◽  
K. CLARK ◽  
P. C. CANFIELD
Keyword(s):  
Magnetic Field ◽  
Transition Temperature ◽  
Single Crystal ◽  
Critical Field ◽  
Superconducting Transition Temperature ◽  
Magnetic Transition ◽  
Upper Critical Field ◽  
Superconducting Transition ◽  
Large Anisotropy ◽  
The Magnetic Field

In-plane resistance as a function of magnitude and direction of the magnetic field and the temperature has been measured for TmNi2B2C from above the superconducting transition temperature at 10.7 K to below the magnetic transition TN=1.5 K. The superconducting upper critical field HC2(T) exhibits a large anisotropy and structure in the vicinity of TN. The magnetoresistance above TC is large and changes sign as the direction of the magnetic field is rotated from in-plane to parallel with the c-axis.

scholarly journals Nonlinear Response of a Superconductor of the Bi-Sr-Ca-Cu-O System to an Alternating Magnetic Field in the Superconducting Transition Temperature Range

2018 ◽  
Vol 185 ◽  
pp. 08005
Author(s):  
Alexander Sergeev ◽  
Igor Golev ◽  
Victoria Gvozdevskaya ◽  
Anastasia Barkalova
Keyword(s):  
Magnetic Field ◽  
Nonlinear Response ◽  
Alternating Magnetic Field ◽  
Resistive State ◽  
Superconducting Transition ◽  
Critical Temperatures ◽  
Temperature Range ◽  
Nonlinear Properties ◽  
Current Voltage ◽  
Current Voltage Characteristics

The nonlinear response of the superconductor of the Bi-Sr-Ca-Cu-O system in the temperature range of the superconducting transition under the action of a harmonic alternating magnetic field is experimentally studied. For multiphase superconductors having in their volume regions with distinct critical temperatures, the effect of odd harmonics in the response signal is observed. The contribution of crystallites and the system of weak bonds between the crystallites in the nonlinear response is singled out. It was found that the nonlinear properties of the investigated samples in the resistive state are determined mainly by the nonlinear current-voltage characteristics of the system of weak bonds between the crystallites.

scholarly journals A single spark model for PSR J2144−3933

2019 ◽  
Vol 492 (2) ◽  
pp. 2468-2480 ◽  
Author(s):  
Dipanjan Mitra ◽  
Rahul Basu ◽  
George I Melikidze ◽  
Mihir Arjunwadkar
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Single Pulse ◽  
Single Component ◽  
Gap Model ◽  
Acceleration Region ◽  
Polar Cap ◽  
Surface Magnetic Field ◽  
Gap Models ◽  
Vacuum Gap

ABSTRACT The partially screened vacuum gap model (PSG) for the inner acceleration region in normal radio pulsars, a variant of the pure vacuum gap model, attempts to account for the observed thermal X-ray emission from polar caps and the subpulse drifting time-scales. We have used this model to explain the presence of death lines and extreme location of PSR J2144−3933 in the $P{-}\dot{P}$ diagram. This model requires maintaining the polar cap near a critical temperature and the presence of non-dipolar surface magnetic field to form the inner acceleration region. In the PSG model, thermostatic regulation is achieved by sparking discharges, which are a feature of all vacuum gap models. We demonstrate that non-dipolar surface magnetic field reduces polar cap area in PSR J2144−3933 such that only one spark can be produced and is sufficient to sustain the critical temperature. This pulsar has a single-component profile over a wide frequency range. Single-pulse polarimetric observations and the rotating vector model confirm that the observer’s line of sight traverses the emission beam centrally. These observations are consistent with a single spark operating within framework of the PSG model leading to single-component emission. Additionally, single-pulse modulations of this pulsar, including lack of subpulse drifting, presence of single-period nulls and microstructure, are compatible with a single spark either in PSG or in general vacuum gap models.

Inhomogeneous Current Distribution in a Bimetal Ferromagnet/Superconductor Film in a Longitudinal Magnetic Field

2009 ◽  
Vol 152-153 ◽  
pp. 462-465 ◽  
Author(s):  
Maxim Avdeev ◽  
Mansur G. Khusainov ◽  
Yurii N. Proshin ◽  
Sergey Tsarevskii
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Current Distribution ◽  
Proximity Effect ◽  
Longitudinal Magnetic Field ◽  
Dirty Limit ◽  
Distribution Versus ◽  
Superconductor Film ◽  
Interface Transparency ◽  
Superconducting Current

The proximity effect of the ferromagnetic metal/superconductor (FM/S) bilayers in а external longitudinal magnetic field is considered in the dirty limit. The critical temperature and the superconducting current distribution versus applied magnetic field’s magnitude, film’s thicknesses and a transparency of the contact is calculated, with taking into account аn umklapp processes possibility on the interface of the FM/S contact. It is shown that superconducting current is strictly inhomogeneous and asymmetrical. It is shown also that the current inhomogeneity depends heavily from the FM/S interface transparency.

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