AC Susceptibility Study of the Inter- and Intragranular Properties in (Bi,Pb):2223 Superconductor

Abstract

The temperature and amplitude of AC field dependencies of both inter-and intragranular T p and T g temperatures of the imaginary peaks of χ′′ has been studied for a sintered single phase (Bi,Pb):2223 superconductor. The AC field dependencies for T p and T g and the relation between inter- and intragrain force densities were discussed by using Müller critical-state model. From the χ′′(T) curve, the values of intergrain magnetic critical current density J cJ was obtained via the application of Bean's critical state model. J cJ (T) dependence near T c agree with the assumption of SNS intergrain junctions.

Thermal properties, texture, second-order stress, and magnetic susceptibility of the Bi1.8Pb0.3Sr2Ca2Cu3.3Ox

“…The second drop is recorded, both from real v 0 as well as from imaginary part, and it is related to the intergranular coupling being recorded at a temperature, T p . At a low magnetic field of 0.4 A m -1 , only the intergranular (Josephson) peak is visible, as it gives the largest contribution to the energy loss [4,5,7,9]. We found linear dependences (solid lines given in Fig.…”

“…Two drops are observed on real part of susceptibility (v 0 ): the first is related to the change of v 0 from zero to negative, that is taking place at a temperature named intragrain critical transition temperature (T g ). The maximum hysteresis loss inside the grain is recorded at T g and is due to the motion of intragranular (Abrikosov) vortices [7]. The second drop is recorded, both from real v 0 as well as from imaginary part, and it is related to the intergranular coupling being recorded at a temperature, T p .…”

“…(17,18) should be interpreted within the framework of Müller critical state model [4,7,9,12,40,41] if we compare them with the similar theoretical linear relations (19,20):…”

“…Soon after the discovery of the Bi-Sr-Ca-Cu-O system by Maeda et al [1], the researchers hardly worked to synthesize and stabilise the high critical temperature (T c ) superconductive, Bi-2223 single phase, due to the very narrow range of temperature for sintering this phase [1][2][3][4][5][6][7][8][9][10][11]. For the Bi-Sr-Ca-Cu-O system were obtained at least three different superconducting phases: Bi 2 Sr 2 CuO 6 (2201 phase with T c of 10-20 K), Bi 2 Sr 2 CaCu 2 O 8 (2212 phase with T c of 80 K), and Bi 2 Sr 2 Ca 2 Cu 3 O 10 (2223 phase with T c of 110 K).…”

“…The alternative current (AC) susceptibility measurements are contact-less and completely non-destructive. Two peaks can be seen on the curve representing the temperature dependence of the imaginary part, v 00 , of the complex AC susceptibility: the first appears at a temperature T g close to T c , and belongs to intragranular losses (motion of intragrain Abrikosov vortices); the second peak is located at a temperature T p lower than T c and corresponds to the intergranular loss due to the motion of Josephson intergranular vortices [7,13]. From magnetic AC susceptibility data, we calculated intragrain critical transition temperature (T g ), and intergranular coupling temperature (T p ), corresponding to the largest contribution to the energy loss versus AC amplitude of the external magnetic field.…”