Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1 '-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.

Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1 '-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.

VOPc maintains an “oxygen-up” orientation and its spin on graphene is S = 1/2: this is an interesting system for qubit applications.

We present a study of the static magnetic properties and spin dynamics in Cobalt valence tautomers (VT), molecules where a low-spin (LS) to high-spin (HS) crossover driven by an intramolecular electron transfer can be controlled by the temperature, by the external pressure or by light irradiation. In the investigated complex, a LS-Co(III) ion bound to a dinegative organic ligand can be reversibly converted into the HS-Co(II) bound to a mononegative one. By combining magnetization measurements with Nuclear Magnetic Resonance (NMR) and Muon Spin Relaxation ({\mu}SR), we have investigated the static magnetic properties and the spin dynamics as a function of the temperature. Moreover, the effect of the external pressure as well as of the infrared light irradiation have been explored through magnetometry and NMR measurements to determine the spin dynamics of the HS state. The photoinduced HS state, which can have a lifetime of several hours below 30 K, is characterized by spin dynamics in the MHz range, which persist at least down to 10 K. The application of an external pressure causes a progressive increase of the LS-HS crossover, which reaches room temperature for pressures around 10 kbar.

A long-term perspective of applications in information and computation technologies has been stimulated by the development of different classes of magnetic molecules: the simplicity of an organic radical where a single spin is stabilized and protected inside a simple organic molecule, the richness of metastable systems like spin crossovers and redox isomers featuring two magnetically inequivalent states accessible via the variation of an external stimulus as well as the nobility of single molecule magnets, in which classical and quantum properties may coexist. Only few of these systems are compatible with nanostructuration, the prerequisite for their local addressing. An overview of the successful attempts of depositing these objects through their self-assembling from solution is provided with the description of the multi-technique approach that has been developed to carefully evaluate the chemistry and the magnetism of monolayers of these classes of molecules.

A new ultralow-temperature setup dedicated to soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) experiments is described. Two experiments, performed on the DEIMOS beamline (SOLEIL synchrotron), demonstrate the outstanding performance of this new platform in terms of the lowest achievable temperature under X-ray irradiation ( T = 220 mK), the precision in controlling the temperature during measurements as well as the speed of the cooling-down and warming-up procedures. Moreover, owing to the new design of the setup, the eddy-current power is strongly reduced, allowing fast scanning of the magnetic field in XMCD experiments; these performances lead to a powerful device for X-ray spectroscopies on synchrotron-radiation beamlines facilities.

The alteration of the properties of single-molecule magnets (SMMs) due to the interaction with metallic electrodes is detrimental to their employment in spintronic devices. Conversely, herein we show that the terbium(iii) bis-phthalocyaninato complex, TbPc2, maintains its SMM behavior up to 9 K on a graphene/SiC(0001) substrate, making this alternative conductive layer highly promising for molecular spintronic applications.

Point-of-care applications and patients' real-time monitoring outside a clinical setting would require disposable and durable sensors to provide better therapies and quality of life for patients. This paper describes the fabrication and performances of a temperature and a pH sensor on a biocompatible and wearable board for healthcare applications. The temperature sensor was based on a reduced graphene oxide (rGO) layer that changed its electrical resistivity with the temperature. When tested in a human serum sample between 25 and 43°C, the sensor had a sensitivity of 110±10Ω/°C and an error of 0.4±0.1°C compared with the reference value set in a thermostatic bath. The pH sensor, based on a graphene oxide (GO) sensitive layer, had a sensitivity of 40±4mV/pH in the pH range between 4 and 10. Five sensor prototypes were tested in a human serum sample over one week and the maximum deviation of the average response from reference values obtained by a glass electrode was 0.2pH units. For biological applications, the temperature and pH sensors were successfully tested for in vitro cytotoxicity with human fibroblast cells (MRC-5) over 24h.

La0.7SrO3MnO3 (LSMO) thin films have proven to act as an efficient spin injection electrode in hybrid organic/inorganic spintronic devices. Optimal control of the chemical composition of the LSMO outermost layer is a key issue in the realization of efficient and reproducible spintronic devices. Low-energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS), empowered by density functional theory (DFT) investigations have been used to reveal the chemical composition of the LSMO termination. The topmost layers consist of a Sr- and Mn-rich phase evolving to the bulk phase via a gradual increase of the La content.

The purpose of this study is to compare the gelling behavior of two molecules: a chiral compound and its achiral counterpart. The chiral partner is characterized by a rigid, chiral pyrrolidine nucleus, while the achiral one contains a flexible diethanolamine moiety. The chiral compound is an already known good organogelator, but also the achiral compound shows remarkable gelling properties. Very interestingly, a small fraction of the chiral compound induces chirality and strong CD effects in its aggregates with the achiral one. The observed chirality amplification corresponds to a peculiar sergeant-and-soldier effect. Molecular modelling and CD calculations suggested a model for the supramolecular assembly of hetero-aggregates that fits the experimental data.

This study describes an innovative strategy to develop advanced multifunctional materials, by embedding magnetic nanoparticles in biodegradable poly(L-lactide) (PLLA) nanospheres. The morphology, size distribution and composition of the nanocomposite particles were investigated by several techniques, demonstrating the successful incorporation of the magnetic nanoparticles into monodisperse polymer nanospheres with average diameter of 130 nm. The effect of the encapsulation on the magnetic behaviour was evaluated by magnetometry techniques and the hyperthermic properties of PLLA embedded nanoparticles were investigated. This study suggested that the combination of the hydrophilic, biocompatible polyvinyl alcohol (PVA), used as surfactant, with the biodegradable and biocompatible PLLA and superparamagnetic nanoparticles is a promising strategy worth further implementing to obtain a magneto-active nanocomposite suitable for biomedical applications such as magnetic cell targeting and drug delivery with thermally induced release. (C) 2014 Elsevier Ltd. All rights reserved.

A chiral organogelating scaffold is functionalised with a stable organic radical pendant. The morphology and spectroscopic properties of the gels are investigated as a function of the organogelator concentration and temperature. The combination of AFM and ESR spectroscopy provides firm evidence that the architecture responsible for the formation of the macroscopic gel (i.e., the fibrillar structure) is maintained below the gelling concentration. This opens relevant perspectives in terms of the realisation of complex supramolecular chiral structures incorporating paramagnetic functions, and demonstrates that the ESR technique is suitable as a fast and direct check of the sample state (gel, solution, or small aggregates).

Structural features and magnetic behaviour of TbPc2 thin films sublimated on LSMO and on cobalt surfaces have been investigated by synchrotron-based XNLD and XMCD techniques. Different orientation of the molecules is observed for the two substrates. No significant magnetic interaction with the ferromagnetic substrates is detected.

Nitronyl nitroxides (NitR) are a family of persistent radicals widely used in molecular magnetism and recently suggested as potential candidates for spintronic applications. In this paper we characterize by X-and W-band Electron Paramagnetic Resonance (EPR) spectroscopy the new radical S-4-(nitronyl nitroxide) benzyl ethanethioate (NitSAc) designed for assembling on Au surfaces. We determined the radical magnetic tensors and studied by X-band pulse EPR its spin relaxation behaviour in fluid and glassy solutions of toluene. A comparison with the well known nitroxide 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-oxyl (CTPO) is afforded. The advantages of using NitSAc in technological applications are discussed on the basis of the slow spin relaxation demonstrated by this study.

Molecular magnetism is here presented with emphasis concerning the single molecule magnets (SMMs). The architecture of SMMs is reviewed as well as the various ingredients promoting magnetic anisotropy and the relation between magnetic anisotropy and the dynamics of magnetization. Then it is shown how XAS and XMCD can be unique tools to unravel the magnetic properties of SMM submonolayers grafted on clean surfaces. We bring a special attention to the spectral features associated with the magnetic anisotropy and magnetization dynamics.

Quantum spin in single molecule magnets Single-molecule magnets are molecular complexes with magnetic bistability that may be exploited in information storage applications. Recently it was shown that such a molecular magnetic memory effect is retained for Fe4 clusters when they are wired to a gold surface. Mannini et al . have now tailored the clusters so that they have a preferential orientation and form a self-assembled monolayer on the surface. As a result, it becomes possible to observe a striking effect of single-molecule magnets — quantum tunnelling of the magnetization, which shows up as steps in the magnetic hysteresis loop. This approach may be of use for the design of practical thin-film molecular spintronic devices.

The magnetic properties of a monolayer of Fe4 single molecule magnets grafted onto a Au (111) thin film have been investigated using low energy muon spin rotation. The properties of the monolayer are compared to bulk Fe4. We find that the magnetic properties in the monolayer are consistent with those measured in the bulk, strongly indicating that the single molecule magnet nature of Fe4 is preserved in a monolayer. However, differences in the temperature dependencies point to a small difference in their energy scale. We attribute this to a ~60% increase in the intramolecular magnetic interactions in the monolayer.

A detailed report on the X-ray Magnetic Circular Dichroism (XMCD) investigation of monolayers of Mn12-based single molecule magnets (SMMs) deposited on gold Au(111) is presented. A semi-quantitative analysis of data is provided in order to extract chemical and magnetic information on Mn ions, by comparison with XMCD on bulk samples. This work points that XMCD is a key-tool for the characterization of SMMs-based nanostructured systems. XMCD surface sensitivity and element-specificity will play a fundamental role in the identification of good candidates for SMMs based devices.

A new method to graft Mn12 magnetic clusters to surface has been investigated. Starting from the preparation of a simple monolayer of aromatic sulfur based molecules organised on gold surface, a Mn12 functionalised with similar moieties is included into the bidimensional lattice. This new derivative has been fully characterised in its bulk structural and magnetic features and grafted into two types of preformed self-assembled monolayer on gold and characterised by means of scanning tunneling microscopy. A dependence of the morphology of such adsorbates on the starting monolayer, in terms of the homogeneity of the deposit and isolation of single SMMs has been found and discussed. (C) 2008 Elsevier B.V. All rights reserved.