LaCaBaCu3O7 is a high critical temperature superconductor (HTS) below the Tc = 80 K and its structure is similar to that of YBCO. In this work we study the effect in the irreversibility line and the Curie-Weiss temperature of this superconductor after borate (BO3)3- doping (LaCaBaCu3-x(BO3)xO7-δx=0.2 and 0.3). Interestingly, borate doping enhances the irreversibility line and this effect is probably caused from alteration the arrangement of the oxygen atoms in the crystalline structure. Moreover, the Curie-Weiss temperature (□p) in the normal state increases with doping concentration. Calculated □p for pure LaCaBaCu3O7 is around -98K, this value increases to -75 and 49 K for x=0.2 and 0.3 respectively and indicating transition from antiferromagnetic to ferromagnetic coupling between ions in the structure. This study provides additional data for the magnetic characteristics of doped like-123 crystalline structures with oxyanions.
Bibliographical noteFunding Information:
This work was supported by the European Union program ALBAN (Contract No. E06D101257PE) and the Cambridge overseas Thrust. The work in Japan was supported by the Japan Society for the Promotion of Science (JSPS contract Nº PE10027); Grants-in-Aid for Scientific Research on Innovative Areas (No. 20108011, ˭-Space) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT); a Collaborative Research Project from the Materials and Structures Laboratory (Tokyo Institute of Technology) and the World Class University Program from the Sunchon National University, Korea.
- Curie-weiss temperature
- High temperature superconductor
- Irreversibility line in superconductors