Correlation between superconducting volume fraction and critical current density in copper oxide superconducting systems

✍ Scribed by A. Sedky; M.I. Youssif

• Book ID: 103890023
• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 321 KB
• Volume: 403
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2003.12.020

✦ Synopsis

Superconducting volume fraction (f g ) is calculated from the data of real and imaginary components (v 0 ; v 00 ) of ac susceptibility measurements versus temperature based on EuBCO and BSCCO systems. It is found that the values of f g decrease with increasing ac field amplitude (H m ) for both systems and it is higher in EuBCO system than in BSCCO system. Further, f g shows much steeper decrease in EuBCO system than in BSCCO system. Moreover, the values of f g are found to be more sensitive to the values [T m =T c ðvÞ] rather than T m values (T m is the temperature at the peak of v 00 and T c ðvÞ is the onset temperature of diamagnetism). The same behavior for f g is obtained for both systems by using Ravi expression [Physica C 295 (1998) 277]. Another various parameters such as decoupling field, London penetration depth and average grain size are also calculated and discussed for both systems. On the other hand, our results show a reverse correlation between both f g and critical current density J c , and indicate that the values of J c are controlled by f g variation in this class of materials.