New Stacking Variations of the CE-type Structure in the Metal-Ordered Manganite YBaMn2O6

TL;DR

This paper investigates novel stacking patterns of the CE-type charge and orbital order in YBaMn2O6, revealing new structural arrangements and their relation to magnetic states, advancing understanding of complex manganite structures.

Contribution

It uncovers new stacking variations of the CE-type structure along the c-axis in YBaMn2O6 and links these patterns to magnetic phase transitions.

Findings

Discovered 4-fold periodicity along the c-axis in the paramagnetic phase.

Identified change to different stacking patterns in the antiferromagnetic phase.

Linked stacking pattern variations to Y/Ba order along the c-axis.

Abstract

For the paramagnetic insulating phase in the metal-ordered manganite YBaMn2O6, the so-called CE-type of charge/orbital ordered state was observed within the monoclinic ab-plane, which is most commonly observed for the ordinary half doped manganites. However, TEM revealed a 4-fold periodicity along the c-axis, suggesting a new stacking pattern, where planes of the CE-type are built up according to the sequence [aabb...]. Interestingly, when th system enters into the antiferromagnetic state, this stacking pattern changes into [aaaa...] or [abab], suggesting close interplay between spins and orbitals. These features are discusses in terms of inherent structural alternation, i.e., the Y/Ba order along the c-axis.