High-field and low field magnetoresistance of CoFe nanoparticles elaborated by organometallic chemistry

TL;DR

This study investigates the magnetoresistance properties of CoFe nanoparticles with organic coatings, revealing significant high-field effects below 10 K and inverse low-field tunneling magnetoresistance at very low temperatures.

Contribution

It provides new insights into the magnetotransport behavior of CoFe nanoparticles, highlighting temperature-dependent magnetoresistance phenomena and their dependence on applied voltage.

Findings

High-field magnetoresistance up to 500% below 10 K

Magnetoresistance amplitude decreases with increasing voltage

Inverse low-field tunneling magnetoresistance observed at 1.6 K

Abstract

We report on magnetotransport measurements on CoFe nanoparticles surrounded by an insulating organic layer. Samples were obtained by evaporating a solution of nanoparticles on a patterned substrate. Typical behaviour of Coulomb blockade in array of nanoparticles is observed. High and low field magnetoresistance have been evidenced. Below 10 K, a large high-field magnetoresistance is measured, reaching up to 500 %. Its amplitude decreases strongly with increasing voltage. At 1.6 K, this high-field magnetoresistance vanishes and an inverse low field tunnelling magnetoresistance is observed.