Magnetic molecules are versatile building blocks for quantum computing and molecular spintronics. The molecular spin can encode quantum information in Qbits or even perform logic operations as Qgates with unmatched reproducibility and scalability [1]. In spintronics, that same molecular spin could generate spin currents in molecular-based spin filters, switches or spin valves among other applications [2]. However, the positioning of individual molecules into nanoscale devices, together with the typically insulating character of most molecule-based magnetic materials, challenges their implementation in nanoelectronics.

Here I will show how we overcome these limitations by creating heterostructures that combine magnetic molecules with one-dimensional single-walled carbon nanotubes (SWCNT). SWCNTs can act as electrical and mechanical backbones that protect and sense the molecular spin. Besides, they can be used as vessels to deterministically place the molecules in devices. In particular, I will show the encapsulation of spin cross-over (SCO) molecules within the SWCNT and their placement between nanoscale electrodes [3]. The host SWCNT conductance is modified by the spin state of the guest encapsulated molecules. In turn, the confinement experienced by the molecules is translated into the appearance of a large thermal hysteresis in the SCO molecules. Besides, I will show the mechanical bond of magnetic porphyrin macrocycles embracing SWCNTs [4]. I will show how we place these hybrids in superconducting resonators and how, in the future, this configuration may allow to reach a strong spin-photon coupling at the single molecule level.

[1] Leuenberger and Loss, Nature 410, 789 (2001), E. Moreno-Pineda et al., Chem Soc. Rev. 47, 501(2018)

[2] Pal et al., Nat. Commun. 10, 1 (2019)

[3] Villalva et al., Nat. Commun. 2021. DOI: 10.1038/s41467-021-21791-3

[4] de Juan-Fernández et al., Chem Sci 9, 6779 (2018)