Giant hysteretic magnetoresistance accompanying the Mott transition and spin-glass state in organic metal

TL;DR

This paper reports giant hysteretic magnetoresistance in an organic metal near the Mott transition, driven by a spin-glass state, revealing a new class of extreme magnetoresistance mechanisms influenced by strong electronic correlations.

Contribution

It introduces a simple model explaining the hysteretic magnetoresistance linked to spin-glass states and charge-spin entanglement in organic metals, expanding understanding of magnetoresistance phenomena.

Findings

Giant hysteretic magnetoresistance observed at low temperatures.

Isotropic hysteresis excludes orbital effects as the cause.

Strong influence of spin-glass state on magnetoresistance.

Abstract

The giant magnetoresistance with a huge hysteresis is observed in the organic metal k-(BEDTTTF)2Hg(SCN)2Br at low temperature in a pressure interval around 3 kbar of a width ~1 kbar. The hysteretic magnetoresistance is isotropic with respect to the direction of magnetic field, which excludes the orbital effect of magnetic field as its origin. The observed temperature and magnetic-field dependence of this hysteresis and of its relaxation time indicates the strong influence of spin-glass state on magnetoresistance. Although a quantitative theory of this effect, originating from strong electronic correlations, requires complex numerical calculations, we suggest its explanation and a simple model which qualitatively describes the observed magnetoresistance behavior and shows a strong charge-spin entanglement. The proposed effect suggests a new class of extreme magnetoresistance mechanisms.