Effect of magnetic fullerene on magnetization reversal created at the Fe/C60 interface

Srijani Mallik,Stefan Mattauch,Subhankar Bedanta,Thomas Brückel,Manas Kumar Dalai

doi:10.1038/s41598-018-23864-8

Abstract

Probing the hybridized magnetic interface between organic semiconductor (OSC) and ferromagnetic (FM) layers has drawn significant attention in recent years because of their potential in spintronic applications. Recent studies demonstrate various aspects of organic spintronics such as magnetoresistance, induced interface moment etc. However, not much work has been performed to investigate the implications of such OSC/FM interfaces on the magnetization reversal and domain structure which are the utmost requirements for any applications. Here, we show that non-magnetic Fullerene can obtain non-negligible magnetic moment at the interface of Fe(15 nm)/C60(40 nm) bilayer. This leads to substantial effect on both the magnetic domain structure as well as the magnetization reversal when compared to a single layer of Fe(15 nm). This is corroborated by the polarized neutron reflectivity (PNR) data which indicates presence of hybridization at the interface by the reduction of magnetic moment in Fe. Afterwards, upto 1.9 nm of C60 near the interface exhibits magnetic moment. From the PNR measurements it was found that the magnetic C60 layer prefers to be aligned anti-parallel with the Fe layer at the remanant state. The later observation has been confirmed by domain imaging via magneto-optic Kerr microscopy.

Highlights

Organic spintronics is an emerging field in 21st century both from fundamental research and application point of view1,2
Among various available organic semiconductor (OSC), Buckminsterfullerene (C60) has drawn immense research interest in organic spintronics because it exhibits the following properties viz. low spin orbit coupling8,9, large spin diffusion length at room temperature, thermal and mechanical resilience, generation of transient triplet state and required mobility to be used in organic field effect transistors (OFETs
We have studied the magnetic interface in bilayer of epitaxial Fe/C60 by polarized neutron reflectivity (PNR) and quantified the induced magnetic moment in the organic layer

Summary

Introduction

Organic spintronics is an emerging field in 21st century both from fundamental research and application point of view. The major aspects in OSC/FM multilayers such as spin injection, tunneling magnetoresistance (TMR), giant magnetoresistance (GMR), hybrid interface properties are observed recently. The second aspect is to understand the effect of the magnetic hybridized OSC layer on the magnetic properties viz. An inverse spin reorientation transition from in-plane to out-of-plane was observed due to the local hybridization between C60 pz and Co dz orbitals26 In this context, it is very important to understand the effect of such magnetic interface in FM/OSC layers on the magnetization reversal which is very much necessary for applications of these heterostructures in any spintronic devices. Further we studied the magnetization reversal process in such bilayers and compare it with the single Fe film to elucidate the effect of the magnetic interface on the domain structure

Methods

Results

Conclusion