Abstract
In this work, we study the long-term aging effect caused by Fe atoms in the superconductor CaLaBa{Cu1 - xFex}3O7 - δ with 0 ≤ x ≤ 0.07. XRD confirms that this system has a YBCO-like structure. The critical temperature (Tc) is strongly affected by aging and depends on the amount of Fe in the structure. Room temperature Mössbauer spectroscopy reveals the presence of the typical species A, B-B′, C and new species E′ and F. Interestingly; A, which corresponds to the Fe3+ atom located in the Cu(1) of the chains with spin Sz = 3/2, shows a drastic reduction which means migration to the species B, B′ and C. Species B and B′ correspond to the Fe3+ in the Cu(2) site forming planar quasi-octahedral and planar square pyramidal, while the C specie is a square pyramidal with O(5) respectively (spin Sz = 3/2 in all these cases). Aging causes loss of superconductivity in the samples with 5 and 7% of iron content.
Original language | English |
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Pages (from-to) | 119-124 |
Number of pages | 6 |
Journal | Hyperfine Interactions |
Volume | 203 |
Issue number | 1-3 |
DOIs | |
State | Published - Nov 2011 |
Externally published | Yes |
Bibliographical note
Funding Information:Acknowledgements This work was supported by the Vice-council of Research of the University of San Marcos (Contract No. 091301051). The work in Cambridge was supported by the European Union program ALBAN (Contract No. E06D101257PE). The work in Japan was supported by the Japan Society for the Promotion of Science (JSPS contract No PE10027). The work in Japan was also partially supported by Grants-in-Aid for Scientific Research on Innovative Areas (No. 20108011, π-Space) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT); a Collaborative Research Project of the Materials and Structures Laboratory (Tokyo Institute of Technology) and the World Class University Program of the Sunchon National University, Korea. The authors are indebted to Mirtha Pillaca for the XRD measurements and Miriam Mejía for the Mössbauer measurements.
Keywords
- Aging effect
- Cuprates
- Mössbauer spectroscopy
- Spatial group P4/mmm