Compact cryogenic Kerr microscope for time-resolved studies of electron spin transport in microstructures

TL;DR

This paper presents a compact cryogenic Kerr microscope capable of time-resolved, spatially-resolved studies of electron spin transport in microstructures under high magnetic fields, advancing spintronics research.

Contribution

It introduces a novel, compact cryogenic Kerr microscope designed for high-resolution, time-resolved spin transport measurements in microstructures within high-field magnets.

Findings

Successfully measured spin diffusion in GaAs/AlGaAs heterostructures.

Demonstrated operation at 4.2 K and 7 Tesla magnetic field.

Achieved ~1 micron spatial resolution in spin transport studies.

Abstract

A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configuration. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of semiconductor microstructures with ~1 micron spatial resolution. The microscope was designed to study spin transport, a critical issue in the field of spintronics. It is thus possible to generate spin polarization at a given location on a microstructure and probe it at a different location. The operation of the microscope is demonstrated by time-resolved measurements of micrometer distance diffusion of spin polarized electrons in a GaAs/AlGaAs heterojunction quantum well at 4.2 K and 7 Tesla.