Measurement of the local Jahn-Teller distortion in LaMnO_3.006

TL;DR

This study measures the local Jahn-Teller distortion in LaMnO_3.006 using atomic pair distribution function analysis, directly capturing local structural details without assuming long-range order, and finds consistency with average structure data.

Contribution

It provides a direct measurement of local Jahn-Teller distortions in LaMnO_3.006, confirming long-range orbital order through local structural analysis.

Findings

Local Jahn-Teller distortion shows 2 short, 2 medium, 2 long bonds.

Good agreement between local PDF analysis and average Rietveld refinements.

Local and average structures are consistent in stoichiometric LaMnO_3.

Abstract

The atomic pair distribution function (PDF) of stoichiometric LaMnO_3 has been measured. This has been fit with a structural model to extract the local Jahn-Teller distortion for an ideal Mn(3+)O_6 octahedron. These results are compared to Rietveld refinements of the same data which give the average structure. Since the local structure is being measured in the PDF there is no assumption of long-range orbital order and the real, local, Jahn-Teller distortion is measured directly. We find good agreement both with published crystallographic results and our own Rietveld refinements suggesting that in an accurately stoichiometric material there is long range orbital order as expected. The local Jahn-Teller distortion has 2 short, 2 medium and 2 long bonds.