Role of Magnetic Exchange Energy on Charge Ordering in RSFO (R=La, Pr, and Nd)

TL;DR

This study uses inelastic neutron scattering to analyze how magnetic exchange energies influence charge ordering in R$_{1/3}$Sr$_{2/3}$FeO$_{3}$ compounds, revealing that magnetic interactions can stabilize charge order, with stability decreasing from La to Nd variants.

Contribution

It provides the first quantitative analysis of the magnetic exchange energy ratio and its role in stabilizing charge order in R$_{1/3}$Sr$_{2/3}$FeO$_{3}$ compounds.

Findings

Magnetic exchange energy ratio |J$_F$/J$_{AF}|$ correlates with charge order stability.

The ratio is large enough in La and Pr compounds to stabilize charge order.

The ratio decreases in Nd, indicating destabilization of charge order.

Abstract

Inelastic neutron scattering is applied to study the role of magnetism in stabilizing the charge ordered state in \emph{R}$_{1/3}$Sr$_{2/3}$FeO$_{3}$ (\emph{R}SFO) (\emph{R} = La, Pr, and Nd). The ratio of the ferromagnetic exchange energy (J$_F$) and antiferromagnetic exchange energy (J$_{AF}$), |J$_F$ /J$_{AF}|, is a key indicator of the stability of the charge ordered and antiferromagnetic ordered state. This ratio is obtained from the spin wave spectrum by inelastic neutron scattering and is sufficiently large to suggest that the magnetic exchange energy alone can stabilize the charge ordered state in La$_{1/3}$Sr$_{2/3}$FeO$_{3}$ and Pr$_{1/3}$Sr$_{2/3}$FeO$_{3}$. The exchange ratio decreases from La$_{1/3}$Sr$_{2/3}$FeO$_{3}$ to Nd1$_{1/3}$Sr$_{2/3}$FeO$_{3}$ which indicates a gradual destabilization of the magnetic exchange mechanism for charge ordering in correspondence with the observed reduction in the ordering temperature.