Excess oxygen in La_{2-x}Sr_xCoO_4

TL;DR

This study calculates excess oxygen levels in La_{2-x}Sr_xCoO_{4+y} using doping and stripe incommensurability, revealing a preference for square-root dependence and an extended oxygen range aligning with the LTO phase.

Contribution

It introduces a method to determine non-stoichiometric oxygen content based on stripe incommensurability and doping, clarifying the oxygen range in relation to structural phases.

Findings

Square-root dependence of stripe incommensurability is favored.

Excess oxygen extends to x < 0.4, not x < 0.3.

Extended oxygen range coincides with the LTO phase.

Abstract

The amount of non-stoichiometric oxygen in La_{2-x}Sr_xCoO_{4+y} is calculated from Sr doping, x, and the measured stripe incommensurability 2delta for x = 1/4 and x = 1/3 based on a linear or square-root dependence of delta(x, y). The results favor the square-root dependence and indicate that the range of excess oxygen extends to x < 0.4 instead of to x < 0.3 as previously thought, coinciding with the low-temperature orthorhombic (LTO) phase.