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Superconductivity with transition temperature up to 80 K for TbSr2Cu2.7Mo0.3O7+δ |
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| Authors: | V.P.S. Awana Anurag Gupta E. Takayama-Muromachi M. Karppinen S.K. Malik V. Ganesan |
| Affiliation: | a National Physical Laboratory, K.S. Krishnan Marg, New Delhi 110012, India b National Institute for Materials Science, 1-1, Namiki, 305-0044, Tsukuba, Ibaraki, Japan c Materials and Structures Laboratory, Tokyo Institute of Technology, 226-8503 Yokohama, Japan d Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India e Graduate Center for Materials Research, University of Missouri, Rolla, MO 65409, USA f Inter-University Consortium for DAE Facilities, University Campus, Khandwa Road, Indore 452017, MP, India |
| Abstract: | A Tb-123 phase with the composition, TbSr2Cu2.7Mo0.3O7+δ, has been synthesized in single-phase form by the solid-state reaction route. Its phase purity has been confirmed from neutron powder diffraction studies. The as-synthesized Tb-123 sample does not show superconductivity down to 5 K. On the other hand, an unusually high antiferromagnetic ordering temperature (TN) of around 7 K is seen for the Tb moments. After 120-atm-O2 post-annealing, bulk superconductivity is achieved in this compound with a superconducting transition temperature (Tc) of about 30 K, without any significant effect on TN. To achieve higher oxygen content and higher Tc, the as-synthesized sample was subjected to high-pressure oxygenation, carried out in a closed cell, at 5 GPa and 400 °C in the presence of AgO as an excess-oxygen source. This sample exhibited superconductivity onset at around 80 K with a Meissner fraction larger than 10% at 5 K. Our observation of superconductivity at 80 K is the highest Tc to-date for the Tb-123 type compounds. |
| Keywords: | 74.25Fy 74.25Ha 74.72Jt |
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