Spin valve effect by ballistic transport in ferromagnetic metal (MnAs) / semiconductor (GaAs) hybrid heterostructures

TL;DR

This paper demonstrates a large spin valve effect via ballistic transport in MnAs/GaAs hybrid heterostructures, showing potential for spintronic devices without high tunnel barriers.

Contribution

It introduces a novel approach to achieve significant spin valve effects using ballistic transport in fully epitaxial ferromagnetic/semiconductor heterostructures.

Findings

Large magnetoresistance observed despite small interface barrier

Ballistic transport enables spin valve effect without high tunnel barriers

Ferromagnetic MnAs nanoparticles effectively act as spin injectors and detectors

Abstract

We demonstrate the spin valve effect by ballistic transport in fully epitaxial MnAs ferromagnetic metal / GaAs semiconductor / GaAs:MnAs granular hybrid heterostructures. The GaAs:MnAs material contains ferromagnetic MnAs nanoparticles in a GaAs matrix, and acts as a spin injector and a spin detector. Although the barrier height of the GaAs/MnAs interface was found to be very small, relatively large magnetoresistance was observed. This result shows that by using ballistic transport, we can realize a large spin valve effect without inserting a high tunnel barrier at the ferromagnetic metal / semiconductor interface.