A Spray‐Based Technique for the Production of MnS Thin Films

A spray‐based technique, originally developed for the production of semiconductor nanocrystals, is utilized for the preparation of high‐quality nanocrystalline thin films, as demonstrated with manganese sulfide. The films are formed by the use of pneumatic‐assisted thermospray or pneumatic nebulizers. Our simple, low‐cost, and low‐temperature process results in a dense and phase‐pure grain structure. The concepts and benefits of this technique are described and discussed. The film characteristics show dependence on the experimental parameters, in particular the rate of solvent vaporization. Three alternative film formation mechanisms are suggested for cases with varied experimental conditions.     

Construction of Nitronyl Nitroxide‐Based 3d–4f Clusters: Structure and Magnetism

Three unprecedented nitronyl nitroxide radical‐bridged 3d–4f clusters, [Ln₂Cu₂(hfac)₁₀(NIT‐3py)₂(H₂O)₂](Ln^III=Y, Gd, Dy), have been obtained from the self‐assembly of Ln(hfac)₃, Cu(hfac)₂, and the radical ligand. The Dy complex shows a slow relaxation of magnetization, representing the first nitronyl nitroxide radical‐based 3d–4f cluster with single‐molecule magnet behavior.     

Can CH⋅⋅⋅π Interactions Be Used To Design Single‐Chain Magnets?

This theoretical study suggests that CH???π stacking interactions between monomeric units can be used to design novel single‐chain magnets (SCMs), as the sign of coupling is predictable and such chains inherently yield negative axial anisotropy, a condition often difficult to achieve in conventional SCMs.     

Recent Developments in Lanthanide Single‐Molecule Magnets

Single‐molecule magnets (SMMs) exhibiting slow relaxation of magnetization of purely molecular origin are highly attractive owing to their potential applications in spintronic devices, high‐density information storage, and quantum computing. In particular, lanthanide SMMs have been playing a major role in the advancement of this field because of the large intrinsic magnetic anisotropy of lanthanide metal ions. Herein, some recent breakthroughs that are changing the perspective of the field are highlighted, with special emphasis on synthetic strategies towards the design of high‐performance SMMs.     

Passive effects of rare-earth permanent magnets on flexible conductive structures

The paper presents a theoretical and experimental study of vibrating structures where paramagnetic or diamagnetic systems interact with rare-earth passive magnets.The theoretical model of the system is focused on the damping properties of permanent magnets and on their interactions with the dynamic behaviour of an Euler–Bernoulli beam. In particular, the magnetic model is based on the analogy of the equivalent currents method in a quasi-static open-circuit-type configuration and it is used to determine the influence of eddy currents on the dynamic behaviour of conducting material structures. The magnetic effects are characterised by a viscous-type damping and by a stiffening dynamic effect of the structure, called “phantom effect”.The authors present the experimental outcomes for uniform cantilever clamped-free beams of different kinds of paramagnetic or diamagnetic conducting materials. It appears that the system frequency response can be modified by the presence of a pair of concordant or discordant permanent magnets of high residual induction settled at the free end.Through the comparison between theoretical and experimental results, the paper demonstrates the validity of the model, that is able to describe both the above mentioned effect of dynamic stiffening of the structure and the considerable localised damping properties in paramagnetic or diamagnetic materials having low electric resistivity.     

Spectroscopic and magnetic investigations of actinide‐based nanomagnets

Magnetic exchange is an essential feature of transition‐metal nanomagnets because it combines the relatively low spin‐only moments of several ions into a “giant spin” ground state, which can make slow magnetic relaxation very favorable in an axially anisotropic environment. In contrast, most of the early research on lanthanide‐based complexes focused on single‐ion magnets, where the required large moment is generated by the unquenched orbital contribution (which is parallel to the spin in heavy rare earths). With their unfilled 5f electronic shell being on the verge between localization and itinerancy, actinides are expected to combine the best of both 3d and 4f metals in terms of exchange and anisotropy, and are therefore under consideration as potential building blocks for the next generation of single‐molecule magnets. In this Perspective, a review of the recent development in this field is given, and some discrepancies between the spectroscopic and magnetic data are discussed. © 2014 European Commission. International Journal of Quantum Chemistry published by Wiley Periodicals, Inc.     

One‐step electrodeposition of amorphous carbon films containing WO3 with high conductivity and good wettability

Tungsten trioxide‐incorporated hydrogenated amorphous carbon (WO₃/a‐C:H) films have been fabricated on a single‐crystal silicon wafer by liquid phase electrodeposition using methanol as carbon source and tungsten carbonyl as incorporated reagent. The morphology, composition and structure of the films have been investigated by SEM, XPS, Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM), respectively. The effects of WO₃ incorporation on the electrical and wetting properties were studied in detail. The characterization results showed that tungsten trioxide nanocrystalline particles with diameters in the range of 10–20 nm were homogenously embedded in the amorphous carbon films. Also, the electrical conductivity and wetting ability of the films were strongly improved due to the contribution of the tungsten trioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co)

Cyanide‐bridged metal complexes of [Fe₈M₆(μ‐CN)₁₄(CN)₁₀ (tp)₈(HL)₁₀(CH₃CN)₂][PF₆]₄?n CH₃CN?m H₂O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1H‐pyrazole), tp^?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2₁/n. They have tetradecanuclear cores composed of eight low‐spin (LS) Fe^III and six high‐spin (HS) M^II ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐Fe^II)₃(LS‐Fe^III)₅(HS‐Co^II)₃(LS‐Co^III)₃] and the [(LS‐Fe^III)₈(HS‐Co^II)₆] states.     

Capping ligand perturbed slow magnetic relaxation in dysprosium single-ion magnets

Single-ion magnets 1 and 2 and their diamagnetic analogues 3 and 4 for magnetic-site dilution were obtained through substitution of the coordinated water molecules of [Ln(TTA)(3)(H(2)O)(2)] (Ln=Dy (1, 2), Y (3, 4); TTA=4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate) by 2,2'-bipyridine (1, 3) and 1,10-phenanthroline (2, 4) capping ligands. Their structures and magnetic properties were investigated with the goal of identifying features relevant to modulating relaxation dynamics of single-ion magnets. The metal ions in all complexes adopt an approximately square-antiprismatic (SAP) O(6)N(2) coordination environment. The SAP polyhedrons for both 1 and 2 show slight longitudinal compression, while the coordination sphere of 1 deviates more from an ideal SAP than that of 2, as indicated by the skew angles of the SAP environment. The similar values of U(eff) for the two magnetically diluted samples imply nearly the same distribution of low-lying states for their Dy(III) centers, which is consistent with the slight axial contraction observed for 1 and 2 and further corroborated by ligand-field analysis. The fast quantum tunneling rate τ(QTM) of 1, which is about ten times faster than that of 2, can presumably be associated with the larger rotation of the SAP surroundings. This distortion may result in a significant transverse anisotropy terms, and thus strongly affect the dynamic behavior of the system.