AC susceptibility of grains and matrix for high-Tc superconductors

Chen, D.-X.; Sanchez, Alvaro; Puig, T.; Martínez, Laura Martínez; Muñoz, J.S.

doi:10.1016/0921-4534(90)90090-2

Cited by 86 publications

(27 citation statements)

References 36 publications

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“…35 Research later concentrated on ͑H m , f͒ of sintered hightemperature superconductors at T = 77 K. In this case, since the entire coil assembly is immersed in liquid nitrogen, H m may be easily increased to 3 ϫ 10 4 A / m, so that both the intergranular J c and the properties of the grains can be studied. [36][37][38] For tapes, films, rings, and disks with high J c , the high-field ac susceptometer mentioned above 12 allows H m to be as large as 10 5 A / m.…”

Section: E Materials Research Using Homemade Ac Susceptometers Calibmentioning

confidence: 99%

Calibration of low-temperature ac susceptometers with a copper cylinder standard

Chen

Skumryev

2010

Review of Scientific Instruments

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A high-quality low-temperature ac susceptometer is calibrated by comparing the measured ac susceptibility of a copper cylinder with its eddy-current ac susceptibility accurately calculated. Different from conventional calibration techniques that compare the measured results with the known property of a standard sample at certain fixed temperature T, field amplitude H m , and frequency f, to get a magnitude correction factor, here, the electromagnetic properties of the copper cylinder are unknown and are determined during the calibration of the ac susceptometer in the entire T, H m , and f range. It is shown that the maximum magnitude error and the maximum phase error of the susceptometer are less than 0.7% and 0.3°, respectively, in the region T = 5 -300 K and f = 111-1111 Hz at H m = 800 A / m, after a magnitude correction by a constant factor as done in a conventional calibration. However, the magnitude and phase errors can reach 2% and 4.3°at 10 000 and 11 Hz, respectively. Since the errors are reproducible, a large portion of them may be further corrected after a calibration, the procedure for which is given. Conceptual discussions concerning the error sources, comparison with other calibration methods, and applications of ac susceptibility techniques are presented.

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Section: E Materials Research Using Homemade Ac Susceptometers Calibmentioning

confidence: 99%

Calibration of low-temperature ac susceptometers with a copper cylinder standard

Chen

Skumryev

2010

Review of Scientific Instruments

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“…As can be seen in Fig. 1 fundamental susceptibility completed at a short temperature width is related to homogeneity [18] and the effective grain volume fraction f g is determined from the height of the plateau of c 0 1 [19]. It can be concluded that the homogeneity and the effective volume fraction are improved with increasing pressing pressure.…”

Section: Effect Of Pressing Pressurementioning

confidence: 87%

“…The main difference between magnetic susceptibility measurements are the field at which the maximum of c 00 1 and the height of the plateau of c 0 1 occurred. In order to calculate J cm , the effective grain volume fraction f g determined from the height of the plateau of the c 0 1 must be known [19]. We have fitted the complex susceptibility of the matrix using the magnetization equation derived by Chen and Goldfarb [21] for the model of Kim et al This fit is only performed to a characteristic point c 00 m; max for each sample.…”

Section: Effects Of Directional Cooling Temperature Ratementioning

confidence: 99%

Effects of Texturing Mechanisms on the Critical Current Density in Sintered High-Tc Bi-2223 Superconductors

Ozogul

Aydinuraz

2001

phys. stat. sol. (a)

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Ac susceptibility measurements on ceramic samples with the nominal composition of Bi 1:8 Pb 0:4 Sr 2 Ca 2 Cu 3 O 10Àd prepared by various pressing pressures on the pellets (355, 533, 711 and 1067 MPa) and different directional cooling temperature rates (20, 10, and 5 C/h) using a directional solidification approach with a stationary Pt crucible in a strong temperature gradient have been carried out. The intergranular critical current density (J cm ) distribution has been calculated from ac susceptibility measurements by using Bean's and Kim's critical state models. It is observed that the critical current density improved with increasing pressing pressure and decreasing directional cooling temperature rates.

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“…We can extract matrix susceptibility χ m and χ m from the measured susceptibility χ and χ using the following equations (Refs. [9,14]):…”

Section: Methodsmentioning

confidence: 99%

AC susceptibility study in the single-phase Bi-2223 system

et al. 2005

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We have found that the composition, Bi1.2Pb0.33Sr1.54Ca2.06Cu3Oy which is comparatively poorer in Bi and Sr with respect to 2 : 2 : 2 : 3, a single-phase 110 K superconductor can be obtained. Such polycrystalline samples have been synthesized by two different methods. The synthesized samples have been characterized by their X-ray diffraction patterns and temperature dependence of DC electrical resistivity and AC susceptibility down to 20 K have been carried out. The samples have been identified as having single phase with a sharp transition. The results of their AC susceptibility have been analysed using Clem's critical state model. The effective volume fraction of the grains and the temperature dependence of the intergranular current density have been estimated.

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AC susceptibility of grains and matrix for high-Tc superconductors

Cited by 86 publications

References 36 publications

Calibration of low-temperature ac susceptometers with a copper cylinder standard

Calibration of low-temperature ac susceptometers with a copper cylinder standard

Effects of Texturing Mechanisms on the Critical Current Density in Sintered High-Tc Bi-2223 Superconductors

AC susceptibility study in the single-phase Bi-2223 system

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