Cation-ordering effects in the single layered manganite La(2/3)Sr(4/3)MnO4

TL;DR

This study investigates how cation order influences magnetic and electronic properties in La(2/3)Sr(4/3)MnO4 films, revealing significant effects on magnetic anisotropy, transport mechanisms, and Mn 3d orbital states.

Contribution

It demonstrates that cation ordering can substantially modify the magnetic and electronic ground states in 2D manganites, a novel insight into correlated electron systems.

Findings

Cation order affects magnetic anisotropy up to 130 K.

Low temperature transport varies with cation arrangement.

Differences in Mn 3d orbital occupancy linked to cation order.

Abstract

We have synthesized epitaxial La(1-x)Sr(1+x)MnO4 (x=1/3) films as random alloys and cation-ordered analogues to probe how cation order affects the properties of a 2D manganite. The films show weak ferromagnetic ordering up to 130 K, although there is a dramatic difference in magnetic anisotropy depending on the cation order. While all films exhibit similar gapped insulator behavior above 130 K, there is a significant difference in the low temperature transport mechanism depending on the cation order. Differences in magnetic anisotropy and low temperature transport are consistent with differences in Mn 3d orbital occupancies. Together this work suggests that cation ordering can significantly alter the Mn 3d orbital ground state in these correlated electron systems.