Tuning Spin Current Injection at Ferromagnet/Non-Magnet Interfaces by Molecular Design

TL;DR

This study demonstrates that molecular design of organic semiconductors can systematically tune spin injection efficiency and spin diffusion length at ferromagnet/non-magnet interfaces, advancing organic spintronics.

Contribution

It introduces a method to control spin injection and diffusion in organic semiconductors through molecular and interfacial engineering.

Findings

Spin injection efficiency is tunable via molecular structure.

Spin diffusion length can be adjusted by side chain substitution.

Interfacial properties critically affect spin transport.

Abstract

There is a growing interest in utilizing the distinctive material properties of organic semiconductors for spintronic applications. Here, we explore injection of pure spin current from Permalloy into a small molecule system based on dinaphtho[2,3-b:2,3-f]thieno[3,2-b]thiophene (DNTT) at ferromagnetic resonance. The unique tunability of organic materials by molecular design allows us to study the impact of interfacial properties on the spin injection efficiency systematically. We show that both, spin injection efficiency at the interface as well as the spin diffusion length can be tuned sensitively by the interfacial molecular structure and side chain substitution of the molecule.