Frustrated Kondo chains and glassy magnetic phases on the pyrochlore lattice

TL;DR

This paper investigates frustrated itinerant magnetism on the pyrochlore lattice, revealing complex magnetic phases and explaining experimental observations through extensive Monte Carlo simulations of electron fillings.

Contribution

It introduces a new itinerant magnetism model on the pyrochlore lattice and maps out phase diagrams at specific electron fillings, explaining experimental magnetic structures.

Findings

Identification of a glassy magnetic state with specific wavevectors

Phase diagrams at electron fillings n=1/2 and 2/3

Explanation of low-temperature phases in GeFe₂O₄

Abstract

We present an extensive numerical study of a new type of frustrated itinerant magnetism on the pyrochlore lattice. In this theory, the pyrochlore magnet can be viewed as a cross-linking network of Kondo or double-exchange chains. Contrary to models based on Mott insulators, this itinerant magnetism approach provides a natural explanation for several spin and orbital superstructures observed on the pyrochlore lattice. Through extensive Monte Carlo simulations, we obtain the phase diagrams at two representative electron filling fractions $n = 1/2$ and 2/3. In particular, we show that an intriguing glassy magnetic state characterized by ordering wavevectors $\mathbf q = \left( \frac{1}{3},\frac{1}{3}, 1\right)$ gives a rather satisfactory description of the low temperature phase recently observed in spinel GeFe$_2$O$_4$.