Large Magnetoresistance Induced by Quantum Charge Fluctuations in Magnetic Double Dots

TL;DR

This paper investigates how quantum charge fluctuations and magnetic alignment in double ferromagnetic dots lead to large, tunable magnetoresistance effects, with potential implications for spintronic devices.

Contribution

It reveals the impact of quantum charge fluctuations and magnetization orientation on Coulomb peak splitting and magnetoresistance in ferromagnetic double dots.

Findings

Large tunneling magnetoresistance observed near Coulomb peaks.

Magnetoresistance sign can be positive or negative depending on magnetic alignment.

Interdot coupling influences Coulomb peak splitting.

Abstract

We study electron tunneling through two small ferromagnetic dots. Quantum charge fluctuations and interdot coupling make each Coulomb peak of the conductance at zero interdot coupling split across. The interdot tunnel coupling is determined by the relative orientation of magnetizations of the two dots, leading to different splitting energies of the Coulomb peaks in parallel and antiparallel magnetization alignments. As a result, a very large tunneling magnetoresistance occurs near the Coulomb peaks, and its sign may be either positive or negative.