High-frequency spin valve effect in ferromagnet-semiconductor-ferromagnet structure based on precession of injected spins

TL;DR

This paper introduces a high-frequency magnetoresistance mechanism in ferromagnet-semiconductor-ferromagnet structures, leveraging electron spin precession and tunneling, with potential applications in GHz-range magnetic sensing.

Contribution

It presents a novel magnetoresistance effect based on spin precession in FM-S-FM structures with delta-doped interfaces, sensitive at room temperature up to 100 GHz.

Findings

Current oscillates with magnetic field at room temperature.

Sensitivity to magnetic field variations up to 100 GHz.

Amplitude depends on spin polarization at FM-S junctions.

Abstract

New mechanism of magnetoresistance, based on tunneling-emission of spin polarized electrons from ferromagnets (FM) into semiconductors (S) and precession of electron spin in the semiconductor layer under external magnetic field, is described. The FM-S-FM structure is considered, which includes very thin heavily doped (delta-doped) layers at FM-S interfaces. At certain parameters the structure is highly sensitive at room-temperature to variations of the field with frequencies up to 100 GHz. The current oscillates with the field, and its relative amplitude is determined only by the spin polarizations of FM-S junctions at relatively large bias voltage.