Existence of the Co3+ Low Spin State in TbBaCo2O5.5

TL;DR

This study investigates the magnetic structures and spin states of TbBaCo2O5.5, providing evidence for the existence of the Co3+ low spin state through combined NMR and neutron diffraction analyses.

Contribution

It demonstrates that only non-collinear magnetic structures can explain all experimental data, resolving previous controversies about the spin states.

Findings

Confirmation of Co3+ low spin state in TbBaCo2O5.5

Non-collinear magnetic structures fit experimental data

Reconciliation of conflicting magnetic structure proposals

Abstract

NMR studies have been carried out on a single crystal sample of TbBaCo2O5.5 with the oxygen-deficient perovskite structure. We have also carried out neutron diffraction studies and added new results to our previously published data. By analyzing these data, the magnetic structures and the spin states of the system, which have been the subjects of strong controversies, are argued in the ferromagnetic and antiferromagnetic phases. We show that among various magnetic structures ever proposed, only our non-collinear ones can reproduce all experimental results accumulated up to now.