Robustness of the magnetoresistance of nanoparticle arrays

TL;DR

This paper investigates how various factors like electrode polarization, array dimensionality, temperature, disorder, and interactions influence the tunneling magnetoresistance in nanoparticle arrays, revealing conditions for robust TMR effects.

Contribution

It provides a comprehensive analysis of the robustness of TMR in nanoparticle arrays under different physical conditions and disorder effects.

Findings

TMR magnitude and voltage dependence are unaffected by array dimensionality or junction resistance disorder.

Electrode polarization asymmetry alters the shape but not the magnitude of TMR and I-V peaks.

Higher temperature and longer-range interactions tend to reduce the size of TMR peaks.

Abstract

Recent work has found that the interplay between spin accumulation and Coulomb blockade in nanoparticle arrays results in peaky I-V and tunneling magnetoresistance (TMR) curves and in huge values of the TMR. We analyze how these effects are influenced by a polarization asymmetry of the electrodes, the dimensionality of the array, the temperature, resistance or charge disorder and long-range interactions. We show that the magnitude and voltage dependence of the TMR does not change with the dimensionality of the array or the presence of junction resistance disorder. A different polarization in the electrodes modifies the peak shape in the I-V and TMR curves but not their order of magnitude. Increasing the temperature or length of the interaction reduces to some extent the size of the peaks, being the reduction due to long-range interactions smaller in longer arrays. Charge disorder should be avoided to observe large TMR values.