Possible origins of resistive tails and critical currents in high-temperature superconductors in a magnetic field

Kim, D. H.; Gray, K. E.; Kampwirth, R. T.; McKay, D. M.

doi:10.1103/physrevb.42.6249

Cited by 148 publications

(31 citation statements)

References 39 publications

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“…The values of q, determined using equation 4, are in the range of 1.9 -3.6 for our samples. In some other works the value of q have been derived to be 3/2 [16], 2 [17] and 1.53-2.8 [18]. Also, we notice that q increases with the increase of Sc-content, confirming with the results of Shakeripouer et al [19] for Gd-123 doped by Ca and Pr.…”

Section: -Results and Discussionsupporting

confidence: 90%

Magnetoresistance studies of Tl-1223 phase substituted by scandium

Awad

Ibrahim

Mansour

et al. 2008

J. Phys.: Conf. Ser.

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Section: -Results and Discussionsupporting

confidence: 90%

Magnetoresistance studies of Tl-1223 phase substituted by scandium

Awad

Ibrahim

Mansour

et al. 2008

J. Phys.: Conf. Ser.

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“…But, Palstra et al [3] and Kim et al [10] proposed a magnetic field dependent T x (H) instead of T c . In the present investigation, T x (H) is been found by fitting the resistivity data using equations (1) and (2).…”

Section: Resultsmentioning

confidence: 99%

Temperature and field dependence of thermally activated flux flow resistance in Bi2Sr2CaCu2O8+δ superconductor

Sharma

Kumar²,

Awana

2012

Solid State Communications

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We study the temperature dependence of the resistivity as a function of magnetic field in superconducting transition (T c onset -T c R=0 ) region for different Bi 2 Sr 2 CaCu 2 O 8+δ superconducting samples being synthesized using sol-gel method. The superconducting transition temperature (T c R=0 ) of the studied samples is increased from 32 K to 82K by simply increasing the final sintering temperature with an improved grains morphology. On the other hand, broadening of transition is increased substantially with decrease in sintering temperature; this is because T c onset is not affected much with grains morphology. Further broadening of the superconducting transition is seen under magnetic field, which is being explained on the basis of thermally activated flux flow (TAFF) below superconducting transition temperature (T c ). TAFF activation energy (U 0 ) is calculated using the resistive broadening of samples in the presence of magnetic field. Temperature dependence of TAFF activation energy revealed linear temperature dependence for all the samples. Further, magnetic field dependence is found to obey power law for all the samples and the negative exponent is increased with increase in sintering temperature or the improved grains morphology for different Bi-2212 samples. We believe that the sintering temperature and the ensuing role of grain morphology is yet a key issue to be addressed in case of cuprate superconductors.

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“…When one solves the inversion equation, dosed-form solutions may be obtained if the problem is formulated in certain ways and the data is in certain forms. Examples of this method include the Gel'fand-Levitan-Marchenko (GLM) theory when rational reflection coefficient is used and methods of inverting the Riccati equation [5]. The advantage is obviously that the convergence is guaranteed and the speed is excellent.…”

Section: Tub1-2 / 15mentioning

confidence: 99%

Theoretical Analysis of Microwave and Millimeter Wave Integrated Circuits Based on Magnetic Films

Kong¹

1992

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REPORT TYPE AND DATES COVERED 11-13-92In general, the inverse methods can be summarized in three categories. The first one is a data base approach. Whenever a measurement result comes in, it will be compared with all the pre-stored patterns in a library to identify the possible targets. In industry, it is called data interpretation which strongly relies on previous experience. The accumulation of data in the library is a learning process. The advantage of this method is that the unknowns can be identified exactly if such target has been seen before so that the cause and the result are directly connected. The disadvantage is that if the data base is not big enough, the target can not be identified, or if the data base is too big, it will take too much time to search for and match the right pattern. The second method is the iterative approach. A forward model of deducing results from cause has been established before the inversion. When a measurement is obtained, a set of guessed values for the unknowns will be put in the forward model as the possible causes. If the predicted result of the forward model does not match the measurement, an adjusted set of parameters will be used as a new guess. The whole procedure will be repeated until the match is found. During iterations, how to correct the error to reach fastest the convergent value is very important.This procedure is also called optimization or error minimization, which by itself is an active research area. Iterative methods are particularly useful when the solution of an integral equation can not be found in an explicit form. As an example of the iterative methods, the Born approximation approximates the forward model in a linearized form, then iterates towards convergence. The advantage of the iterative approach is that an accurate final solution can be found at a relative fast (compare to data base search) speed. The method is also flexible for different kinds of targets, unlike the data base search where the target has to have been seen before. The disadvantage is that the convergence of iteration is not always guaranteed. There are usually more than one minimum of the cost function. 3The initial guess is sometimes so critical to assure the right convergent result that a Priori information needs to be used. Non-uniqueness is a serious problem in all inversion methods.Sufficient number of measurements are helpful of reducing the degree of non-uniqueness.Formulation of the forward model for the final inversion equation determines how efficient the inversion scheme is, which sometimes also affect the degree of non-uniqueness.A recently developed inversion method referred to as the renormalized Source-TypeIntegral Equation (STIE) approach solves the integral equation derived from the Green's function without the linear approximation. The STIE approach formulates an exact forward model, hence is not restricted to low contrast profiles or weak scattering. The STIE method has been applied to profile inversion problems of the soil moisture and oil formation in bore...

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Possible origins of resistive tails and critical currents in high-temperature superconductors in a magnetic field

Cited by 148 publications

References 39 publications

Magnetoresistance studies of Tl-1223 phase substituted by scandium

Magnetoresistance studies of Tl-1223 phase substituted by scandium

Temperature and field dependence of thermally activated flux flow resistance in Bi2Sr2CaCu2O8+δ superconductor

Theoretical Analysis of Microwave and Millimeter Wave Integrated Circuits Based on Magnetic Films

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