Magnetic molecules & molecular spintronics

  • Molecular spintronics with functional molecules

This project aims at tailoring spintronics devices by molecular engineering using self-assembled monolayers (SAMs) of functional molecules. Our aim is to go beyond the state-of-the-art of fundamental knowledge to develop and evaluate the potential of multifunctional molecular spintronics devices. We use functional molecules controlled by external stimuli (light or electric field) to modify the molecule/electrode spin hybridization in-situ.

Capture d’écran 2020-03-25 à 22.22.43 We report on the phosphonic acid route for the grafting of functional molecules, optical switch (dithienylethene diphosphonic acid, DDA), on La0.7Sr0.3MnO3 (LSMO). A partial light-induced conductance switching between the open and closed forms of the DDA is observed for the LSMO/DDA/C-AFM tip molecular junctions (closed/open conductance ratio of about 8). [L. Thomas et al., Nanoscale (2020)]

A second system is azobenzene derivatives on cobalt electrodes [L. Thomas et al., in preparation].

Main coll.: R. Mattana, P. Seneor (Unité Mixte de Physique CNRS/Thales, France); J. Cornil (LCNM, U. Mons, Belgium); Y. Pei, T. Mallah (ICMMO, CNRS, U. Paris-Saclay, France).

  • Molecular junctions with magnetic molecules

We study electron transport through molecular junctions made of magnetic molecules.

POM-JACSWe have explored a novel surface anchoring mode (organo- amino group−Au surface) in an approach to render magnetically functionalized polyoxometalates (POMs) accessible to charge transport experiments in distinct environments, and we have determined the electronic structure of these metal/magnetic POMs/metal junctions. [X. Yi et al., J. Am. Chem. Soc. (2017)].

Capture d’écran 2020-09-24 à 17.47.04We study the electronic properties of nano-devices made of magnetic nanocrystals of Prussian blue analogues (PBA). We report electron transport measurements through nano-scale devices consisting of 1 to 3 (PBA) nanocrystals connected between two electrodes. We compare two types of cubic nanoparticles, CsCoIIIFeII (15 nm) and CsNiIICrIII (6 nm), with low decay factors β, in the range 0.11 – 0.18  nm-1 and 0.25 – 0.34 nm-1 for  CsCoFe and  CsNiCr nanocrystals, respectively. Conductance values measured for multi-nanoparticle nano-scale devices (2 and 3 nanocrystals between the electrodes) are consistent with a multi-step coherent tunneling in the off-resonance case between adjacent PBAs, a simple model gives a strong coupling (around 0.1 – 0.25 eV) between the adjacent PBA nanocrystals, mediated by electrostatic interactions. [R. Bonnet et al., submitted].

Main Coll. : P. Kögerler (Inst. Inorg. Chem., Aachen univ. & Peter Grünberg Institute, Jülich, Germany), T. Mallah (ICMMO, CNRS, U. Paris-Saclay, France).