Local Light-Induced Magnetization Using Nanodots and Chiral Molecules

TLDR

Miniaturization drives the use of nanostructures, and spintronics—particularly spin‑selective transport through chiral molecules—offers a promising route to reduce power consumption in future integrated circuits. The study demonstrates that chiral molecules combined with nanocrystals can generate local spin‑based magnetization optically at room temperature. A chiral layer transfers spin torque from nanocrystals to a thin ferromagnetic layer without charge transfer, and local perpendicular magnetization is measured with Hall sensors and AFM, while anomalous spin Hall effects are observed at low temperatures. These findings suggest that optically controlled spintronics logic devices could achieve low power consumption, high density, and inexpensive fabrication.

Abstract

With the increasing demand for miniaturization, nanostructures are likely to become the primary components of future integrated circuits. Different approaches are being pursued toward achieving efficient electronics, among which are spin electronics devices (spintronics). In principle, the application of spintronics should result in reducing the power consumption of electronic devices. Recently a new, promising, effective approach for spintronics has emerged, using spin selectivity in electron transport through chiral molecules. In this work, using chiral molecules and nanocrystals, we achieve local spin-based magnetization generated optically at ambient temperatures. Through the chiral layer, a spin torque can be transferred without permanent charge transfer from the nanocrystals to a thin ferromagnetic layer, creating local perpendicular magnetization. We used Hall sensor configuration and atomic force microscopy (AFM) to measure the induced local magnetization. At low temperatures, anomalous spin Hall effects were measured using a thin Ni layer. The results may lead to optically controlled spintronics logic devices that will enable low power consumption, high density, and cheap fabrication.