Magnetic ordering in Gd2Sn2O7: the archetypal Heisenberg pyrochlore antiferromagnet

TL;DR

This study uses neutron diffraction to analyze the magnetic structure of Gd2Sn2O7, confirming it as a prototypical Heisenberg pyrochlore antiferromagnet with dipolar interactions and revealing the role of third-neighbor superexchange in its magnetic ordering.

Contribution

It provides experimental confirmation of the theoretical ground state for a Heisenberg pyrochlore antiferromagnet with dipolar interactions and identifies the influence of third-neighbor superexchange interactions.

Findings

Gd2Sn2O7 has the predicted magnetic ground state for a Heisenberg pyrochlore antiferromagnet.

The magnetic structure differs from Gd2Ti2O7 due to specific third-neighbor superexchange interactions.

Symmetry analysis of neutron diffraction data supports the theoretical model.

Abstract

Low-temperature powder neutron diffraction measurements are performed in the ordered magnetic state of the pyrochlore antiferromagnet Gd2Sn2O7. Symmetry analysis of the diffraction data indicates that this compound has the ground state predicted theoretically for a Heisenberg pyrochlore antiferromagnet with dipolar interactions. The difference in magnetic structures of Gd2Sn2O7 and of nominally analogous Gd2Ti2O7 is found to be determined by a specific type of third-neighbor superexchange interaction on the pyrochlore lattice between spins across empty hexagons.