Sr$_6$Co$_5$0{$_1$$_5$}: non-one-dimensional behavior of a charge ordered structurally quasi-one-dimensional oxide

TL;DR

This study synthesizes and analyzes Sr$_6$Co$_5$O$_{15}$, revealing its non-one-dimensional magnetic and electronic behavior, which deviates from expectations based on its quasi-one-dimensional structure, through experimental and ab initio methods.

Contribution

It provides the first detailed investigation of Sr$_6$Co$_5$O$_{15}$'s magnetic and electronic properties, showing non-traditional behavior for a quasi-one-dimensional oxide.

Findings

Magnetic coupling inside CoO$_3$ chains is not purely ferromagnetic.

Long-range magnetic coupling within chains is very weak.

Thermopower calculations match experimental data, supporting the magnetic ground state model.

Abstract

We have synthesized Sr$_6$Co$_5$O$_{15}$, a quasi-one-dimensional oxide, measured its magnetic properties and calculated its electronic structure by ab initio techniques. We have found strong evidence for its electronic and magnetic behavior not to follow the trend of its structural series. The magnetic coupling inside the CoO$_3$ chains is not purely ferromagnetic, the long-range coupling inside them is very weak. The Co moments are slightly canted due to their large orbital angular momenta being oriented along each particular quantization axis, that is different for each Co$^{4+}$ atom in the structure. Our thermopower calculations are in agreement with the experiment, supporting our model of the magnetic ground state of the compound.