Superconductivity of up to 80 K for Tb-123 - TbSr2Cu2.7Mo0.3O7

TL;DR

This study reports the synthesis of a Tb-123 compound with Mo doping, achieving a record high superconducting transition temperature of 80 K through high-pressure oxygenation, marking the highest Tc among Tb-123 materials.

Contribution

The paper demonstrates a novel synthesis method for Tb-123 with Mo doping and achieves the highest Tc of 80 K among Tb-123 compounds using high-pressure oxygenation.

Findings

Superconductivity at 80 K achieved after high-pressure oxygenation.

Bulk superconductivity observed with a Meissner fraction over 10%.

No significant change in antiferromagnetic transition temperature after oxygenation.

Abstract

The Tb-123 phase has been synthesized in single-phase form with the composition TbSr2Cu2.7Mo0.3O7 by solid-state reaction route and its phase purity is confirmed by neutron powder diffraction experiments. As-synthesized sample does not show superconductivity down to 5 K. An unusually high antiferromagnetic ordering temperature (TN) of around 7 K is seen for Tb. After 120-atm-O2 post-annealing, bulk superconductivity is achieved in the compound at around 30 K, without any significant effect on TN. To achieve higher oxygen content and higher Tc, the as-synthesized sample is subjected to high-pressure oxygenation (HPO) carried out in a closed cell at 5 GPa and 400 oC in the presence of AgO as an excess-oxygen source. This sample exhibited superconductivity onset at around 80 K with a Meissner fraction of larger than 10 % at 5 K. Our observation of superconductivity at 80 K is the highest Tc to-date among the Tb-123 compounds.