Mixed valence on a pyrochlore lattice - LiV2O4 as a geometrically frustrated magnet

TL;DR

This paper investigates the magnetic and electronic properties of LiV2O4, a heavy Fermion spinel with a pyrochlore lattice, highlighting its geometric frustration and proposing theoretical models for its transitions.

Contribution

It extends a tetragonal mean field theory to account for mixed spin tetrahedra in LiV2O4, offering new insights into its magnetic behavior.

Findings

LiV2O4 exhibits features of geometrically frustrated magnets above 40K.

Resistivity exceeds the Mott-Regel limit at room temperature.

Theoretical scenarios for magnetic and electronic transitions are proposed.

Abstract

Above 40K, the magnetic susceptibility of the heavy Fermion spinel LiV2O4 has many features in common with those of geometrically frustrated magnetic insulators, while its room temperature resistivity comfortably exceeds the Mott-Regel limit. This suggests that local magnetic moments, and the underlying geometry of the pyrochlore lattice, play an important role in determining its magnetic properties. We extend a recently introduced tetragonal mean field theory for insulating pyrochlore antiferromagnets to the case where individual tetrahedra contain spins of different lengths, and use this as a starting point to discuss three different scenarios for magnetic and electronic transitions in LiV2O4.