Large Magnetoresistance Ratio in Ferromagnetic Single-Electron Transistors in the Strong Tunneling Regime

TL;DR

This paper investigates transport in ferromagnetic single-electron transistors using a path integral approach, revealing a large magnetoresistance ratio at low temperatures in the strong tunneling regime.

Contribution

It introduces a path integral method to analyze transport in ferromagnetic single-electron transistors beyond traditional tunneling regimes, highlighting conditions for large magnetoresistance.

Findings

Large magnetoresistance ratio at low temperatures in strong tunneling regime

Magnetoresistance only slightly enhanced when thermal energy exceeds charging energy

Applicable to systems with tunnel resistances below quantum resistance

Abstract

We study transport through a ferromagnetic single-electron transistor. The resistance is represented as a path integral, so that systems where the tunnel resistances are smaller than the quantum resistance can be investigated. Beyond the low order sequential tunneling and co-tunneling regimes, a large magnetoresistance ratio at sufficiently low temperatures is found. In the opposite limit, when the thermal energy is larger than the charging energy, the magnetoresistance ratio is only slightly enhanced.