Determination and Control of Oxygen Stoichiometry in the Cuprate Bi2sr2cuo6+D

TL;DR

This study investigates how to precisely control and measure oxygen content in Bi2Sr2CuO6+D, revealing two regimes of oxygen intercalation and providing insights into its doping levels and properties.

Contribution

It offers a detailed quantitative analysis of oxygen non-stoichiometry in Bi2Sr2CuO6+D using thermogravimetric techniques, which was previously limited in literature.

Findings

Oxygen excess varies between 0.14 and 0.18.

Two regimes of oxygen intercalation are identified.

Thermogravimetric methods effectively determine oxygen content.

Abstract

The relatively low Tc of Bi2Sr2CuO6+D allows to study normal-state down to low temperatures and the non-substituted compound is intrinsically strongly overdoped. Hole concentration can be adjusted trough oxygen excess, but few data exist in the literature about the quantitative control of D. The synthesis, achieved in air by solid-state reaction, needs long-time annealing to obtain pure phase with stoichiometric cationic ratios. Thermogravimetric techniques were used to explore oxygen non-stoichiometry. Absolute oxygen content was determined by reduction with hydrogen, while the oxygen exchange was studied between 300 C and 670 C with different PO2. Oxygen excess varies between 0.14 and 0.18, with possibly two regimes of oxygen intercalation. These results are compared to Bi-2212.