ABSTRACT
Exploring properties of magnetic molecules on surfaces using a multitechnique approach
Due to the wealth and the tuneability of their properties, molecular materials stand out as a possible answer to the needs for innovative technologies. The ensemble of magnetic molecules constitutes a rich playground for chemists and physicists toward the development of novel molecular based devices also because of this possibility to finely tune the device properties through proper design of the molecular structure and the assembling of established building blocks following a rational design. This idea explains the huge efforts of molecular magnetism[1] community in the exploration of the use of magnetic molecules for the development of novel devices for the information and computation technologies including spintronics and quantum computation. However a migration from classical materials to future molecular-based devices requires a careful evaluation of the chemical and physical properties of those fragile magnetic systems after that nanostructuration processes have been attempted. A multi-technique approach including X-rays absorption-based spectroscopies become fundamental for the verification that chemistry of molecules and their magnetic features survives to the extreme conditions occurring in single-molecule-device-like environments. Going beyond a morphological characterization allowing to “see” isolated molecular objects, intactness of molecules can be evaluated by using surface sensitive techniques including mass spectrometry and photoelectron spectroscopies that provide a complete overview of the chemical and electronic properties of those systems. X-ray circular magnetic dichroism (XMCD) experiments lead to fundamental steps forward in this demanding exploration by directly accessing to static and dynamic magnetic properties of those systems down to the nanoscale.
Molecules showing slow relaxation of the magnetisation, known as single molecule magnets (SMMs) [2–4], and temperature and light switchable molecular systems like Valence Tautomers (VT) [5]and Spin Crossover compounds (SCO) [6] can be assembled on surfaces by adopting wet-chemistry approaches or sublimating them using high vacuum compatible techniques. Only the combination of several characterization tools allows to demonstrate that their magnetic behavior can be maintained, lost or enhanced by the interaction with surfaces.
