Giant magnetoresistance in quantum magnetic contacts

TL;DR

This paper models quantized conductance and giant magnetoresistance in nanoscale ferromagnetic contacts, highlighting the effects of spin-reversal processes and contact asymmetry, and relates findings to recent experimental results.

Contribution

It provides a theoretical framework for understanding quantized conductance and magnetoresistance in magnetic point contacts, including the influence of spin dynamics and contact asymmetry.

Findings

Magnetoresistance magnitude limited by spin-reversal rates.

Asymmetry in contact cross-section affects giant magnetoresistance.

Theoretical results align with recent experimental observations.

Abstract

We present calculations of quantized conductance and magnetoresistance in nanosize point contacts between two ferromagnetic metals. When conductance is open for only one conduction electrons spin-projection, the magnitude of magnetoresistance is limited by the rate of conduction electron spin-reversal processes. For the case when both spin-channels contribute to the conductance we analyze the influence of the point contact cross-section asymmetry on the giant megnetoresistance. Recent experiments on magnetoresistance of magnetic point contacts are discussed in the framework of the developed theory.