Structural and Electronic Properties of a Triangular Lattice Magnet NaPrTe$_2$ Compared with NaNdTe$_2$ and NaTbTe$_2$

TL;DR

This study investigates the structural and magnetic properties of NaPrTe2, NaNdTe2, and NaTbTe2, revealing a new polymorph of NaPrTe2 with potential for exploring geometrically frustrated lattices.

Contribution

The paper reports the discovery of a new alpha-NaFeO2 structure in NaPrTe2 and compares its properties with related compounds, highlighting its proximity to a phase boundary and potential for lattice control.

Findings

NaPrTe2 has a new alpha-NaFeO2 structure polymorph.

NaPrTe2 shows no long-range magnetic order above 2 K.

NaPrTe2 is near a phase boundary between two structural types.

Abstract

NaPrTe2, NaNdTe2, and NaTbTe2 are found to be triangular lattice magnets with the alpha-NaFeO2 structure, where lanthanoid atoms with 4f electrons form a triangular lattice, based on the structural analysis and physical property measurements of synthesized polycrystalline samples. The alpha-NaFeO2 structure is a new polymorph of NaPrTe2, which has been reported to crystallize in the cubic LiTiO2 structure. Polytypism in NaPrTe2 was discussed based on the structural parameters determined by the Rietveld analysis. NaPrTe2 is suggested to be in the proximity of the phase boundary between the LiTiO2 and alpha-NaFeO2 types, as compared to NaNdTe2 and NaTbTe2, indicating that this compound might be interesting from the perspectives of the dimensional control of geometrically frustrated lattices. The magnetic susceptibility and heat capacity data indicated that NaPrTe2 do not show long-range magnetic order or a spin-glass transition above 2 K.