Spin-state-dependent electrical conductivity in single-walled carbon nanotubes encapsulating spin-crossover molecules

Julia Villalva,Arturo Gamonal,Emilio M Pérez,Carmen J Calzado,Luisa Ruiz-Gonzalez,José Sánchez Costa,Enrique Burzurí,Aysegul Develioglu,Nicolas Montenegro-Pohlhammer,Mar García-Hernández,Eduardo Rial,Rocío Sánchez-De-Armas

doi:10.1038/s41467-021-21791-3

Abstract

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

Highlights

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli
Encapsulation of the SCO compounds within the single-walled carbon nanotubes (SWCNT) cavity seems a rather attractive approach, as the SWCNTs can be robust mechanical shells that protect SCO molecules from the environment and serve as vessels to controllably place them in nanoscale devices[14,15,16,17,18]
We study electron transport through individual SCO@SWCNT heterostructures embedded in nanoscale transistors (Fig. 1c)

Summary

Introduction

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. The SEM and AFM imaging and the current-voltage characteristic measured in the device indicate that one or a few SCO@SWCNT hybrids are bridging the gap between the electrodes

Results

Conclusion