Magnetic properties of PdAs2O6: a dilute spin system with an unusually high N\'eel temperature

TL;DR

This study investigates PdAs2O6's magnetic structure and finds it has a much higher Néel temperature than its 3d-homologue NiAs2O6, despite similar structures, due to differences in electronic exchange interactions.

Contribution

The paper reveals that PdAs2O6 exhibits a significantly higher Néel temperature than NiAs2O6, and explains this through electronic structure calculations and exchange interaction analysis.

Findings

PdAs2O6 has a Néel temperature of 140 K, much higher than NiAs2O6's 30 K.

Magnetic structure of PdAs2O6 is identical to NiAs2O6.

Electronic structure calculations explain the difference in exchange interactions.

Abstract

The crystal structure and magnetic ordering pattern of PdAs2O6 were investigated by neutron powder diffraction. While the magnetic structure of PdAs2O6 is identical to the one of its isostructural 3d-homologue NiAs2O6, its N\'{e}el temperature (140 K) is much higher than the one of NiAs2O6 (30 K). This is surprising in view of the long distance and indirect exchange path between the magnetic Pd$^{2+}$ ions. Density functional calculations yield insight into the electronic structure and the geometry of the exchange-bond network of both PdAs2O6 and NiAs2O6, and provide a semi-quantitative explanation of the large amplitude difference between their primary exchange interaction parameters.