SCIENTIFIC HIGHLIGHTS

Dynamics of intramolecular spin exchange interaction of a nitronyl nitroxide diradical in solution and on surfaces
25 June 2016

In this paper we report the study of the dynamics of a thermally modulated intramolecular spin exchange interaction of a novel diradical nitronyl nitroxide-substituted disulfide in solution and when it is grafted on a gold surface. The structure of this diradical was designed to have flexible chains leading to intramolecular collisions and hence spin exchange interaction, and with an appropriate binding group to be grafted on the gold surface to study its behavior on the surface. In solution, this diradical shows a strong spin exchange interaction between both radicals which is modulated by temperature, but also gold nanoparticles (AuNPs) functionalized with this diradical permit investigation of such a phenomenon in surface-grafted radicals. The spin-labelled AuNP synthesis was optimized to obtain high coverage of spin labels to lead to high spin exchange interaction. The obtained AuNPs were studied by Electron Paramagnetic Resonance (EPR), UV-Vis, and IR spectroscopies, HR-TEM microscopy, Cyclic Voltammetry (CV), Energy Dispersive X-ray analysis (EDX) and Thermogravimetric Analysis (TGA). This inorganic–organic hybrid material also showed dipolar interactions between its radicals which were confirmed by the appearance in the EPR spectra of an |Δms| = 2 transition at half-field. This signal gives direct evidence of the presence of a high-spin state and permitted us to study the nature of the magnetic coupling between the spins which was found to be antiferromagnetic. Self-Assembled Monolayers (SAMs) of these radicals on the Au (111) substrate were also prepared and studied by contact angle, X-Ray Photoelectron Spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Cyclic Voltammetry and EPR. The magnetic as well as the electrochemical properties of the hybrid surfaces were studied and compared with the properties of this diradical in solution. Analogies between the properties of AuNPs with high coverage of radicals and those of SAM were observed.



Hits: 5808
Oxides for new-generation electronics

Dynamics of intramolecular spin exchange interaction of a nitronyl nitroxide diradical in solution and on surfaces



Also at ICMAB

  • Optical Plasmon Excitation in Transparent Conducting SrNbO3 and SrVO3 Thin Films

    Information
    27 July 2021 65 hit(s) Oxides
    From catalysis and flat panel displays to photovoltaics, transparent and conducting transition metal oxides are gaining momentum toward more sustainable and cost-efficient applications. Here it is shown that, without using phase-matching arrangements, bulk plasmons can be excited in continuous epitaxial films of metallic SrVO3 and SrNbO3, with plasma absorption edges at visible range, and tuned mainly by electron correlations and phonon dressing. Films can be made reflective or transparent at whish.
  • Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO3

    Information
    20 July 2021 194 hit(s) Oxides
    The nature of electron-electron and electron-lattice interactions in metallic oxides is revised. The common wisdom is that the strong correlations among electrons determine their properties. Here we argue that the unavoidable coupling between free electrons and the lattice in ionic materials leads to the formation of polarons. These are carriers dressed by a lattice distortion that travel with them and largely determine the transport and some optical properties.
  • A new density-modification procedure extending the application of the recent |ρ|-based phasing algorithm to larger crystal structures

    Information
    13 July 2021 189 hit(s) Oxides
    The incorporation of the new peakness-enhancing fast Fourier transform compatible ipp procedure (ipp = inner-pixel preservation) into the recently published SM algorithm based on |ρ| [Rius (2020). Acta Cryst A76, 489–493] improves its phasing efficiency for larger crystal structures with atomic resolution data. Its effectiveness is clearly demonstrated via a collection of test crystal structures (taken from the Protein Data Bank) either starting from random phase values or by using the randomly shifted modulus function (a Patterson-type synthesis) as initial ρ estimate.
  • Current-Induced Magnetization Control in Insulating Ferrimagnetic Garnets

    Information
    29 June 2021 251 hit(s) Oxides
    The research into insulating ferrimagnetic garnets has gained enormous momentum in the past decade. This is partly due to the improvement in the techniques to grow high-quality ultrathin films with desirable properties and the advances in understanding the spin transport within the ferrimagnetic garnets and through their interfaces with conducting materials. In recent years, we have seen remarkable progress in controlling the magnetization state of ferrimagnetic garnets by electrical means in suitable heterostructures and device architectures.
  • Stabilization of the Ferroelectric Phase in Epitaxial Hf1–xZrxO2 Enabling Coexistence of Ferroelectric and Enhanced Piezoelectric Properties

    Information
    18 June 2021 385 hit(s) Oxides
    Systematic studies on polycrystalline Hf1–xZrxO2 films with varying Zr contents show that HfO2 films are paraelectric (monoclinic). If the Zr content is increased, films become ferroelectric (orthorhombic) and then antiferroelectric (tetragonal). HfO2 shows very good insulating properties and it is used in metal-oxide-semiconductor field-effect devices, while ZrO2 shows good piezoelectric properties, but it is antiferroelectric. In between, Hf0.5Zr0.5O2 shows good ferroelectric properties at the expense of poorer insulating and piezoelectric properties than HfO2 and ZrO2, respectively.

INSTITUT DE CIÈNCIA DE MATERIALS DE BARCELONA, Copyright © 2020 ICMAB-CSIC | Privacy Policy | This email address is being protected from spambots. You need JavaScript enabled to view it.