Carbon Nanotubes: In-Situ Growth of Ultrathin Films of NiFe-LDHs: Towards a Hierarchical Synthesis of Bamboo-Like Carbon Nanotubes (Adv. Mater. Interfaces 6/2014)

Tailoring magnetic properties of electrodeposited thin films of the molecule-based magnet Cr5.5(CN)12 11.5H2O

This paper reports on molecular-based magnetic thin films of Prussian blue analogues (PBA) with high critical temperatures composed of mixed-valence chromium cyanides. The thin films of PBA were synthesized by means of electrodeposition technique. Morphology and magnetic study are presented in a function of electrochemical deposition conditions. We present the electrochemical methods as a promising and effective tool for preparing molecular-based magnetic thin films of Prussian blue analogue.

In-Situ Growth of Ultrathin Films of NiFe-LDHs: Towards a Hierarchical Synthesis of Bamboo-Like Carbon Nanotubes

The synthesis of ultrathin films (UTFs) of NiFe-LDHs has been achieved by means of an in situ hydrothermal approach, leading to a flat disposition of the LDH crystallites on the substrate, in clear contrast to the most common perpendicular orientation reported to date. Experimental factors like time of synthesis or the nature of the substrate, seem to play a crucial role during the growing process. The 2D morphology of the NiFe-LDH crystallites was kept after a calcination procedure, leading to a topotactic transformation into mixed-metal oxide platelets. Hereby, in order to study the catalytic behavior of our samples, a chemical vapor deposition process is explored upon the as-synthesized …

Exchange coupling in an electrodeposited magnetic bilayer of Prussian blue analogues

Bilayers of Prussian blue analogues (PBA) constituted of hard and soft magnets have been fabricated by means of electrochemical deposition. This method affords a good contact between two PBA thin films of nanometer thickness. Complete characterization of the resulting system has been performed, which has allowed the determination of the preservation of the chemical identity of both materials during the electrodeposition and the establishment of a clear interface between them. The magnetic behavior of the bilayer can be explained in terms of an exchange-spring magnet.

Magneto-Optical Properties of Electrodeposited Thin Films of the Molecule-Based Magnet Cr5.5(CN)12·11.5H2O

Prof. E. Coronado , M. Makarewicz , J. P. Prieto-Ruiz , Dr. H. Prima-Garcia , Dr. F. M. Romero Instituto de Ciencia Molecular (ICMol) Universitat de Valencia C/Catedratico Jose Beltran, 2, 46980-Paterna, Spain E-mail: eugenio.coronado@uv.es; helena.prima@uv.es; fmrm@uv.es

Design of Molecular Spintronics Devices Containing Molybdenum Oxide as Hole Injection Layer

Enhancing Light Emission in Interface Engineered Spin-OLEDs through Spin-Polarized Injection at High Voltages

The quest for a spin-polarized organic light-emitting diode (spin-OLED) is a common goal in the emerging fields of molecular electronics and spintronics. In this device, two ferromagnetic (FM) electrodes are used to enhance the electroluminescence intensity of the OLED through a magnetic control of the spin polarization of the injected carriers. The major difficulty is that the driving voltage of an OLED device exceeds a few volts, while spin injection in organic materials is only efficient at low voltages. The fabrication of a spin-OLED that uses a conjugated polymer as bipolar spin collector layer and ferromagnetic electrodes is reported here. Through a careful engineering of the organic/…

Magnetic ordering in an (Fe0.2Cr0.8)1.5[Cr(CN)6] Prussian blue analogue studied with synchrotron radiation based spectroscopies

The appearance of magnetic order in the (Fe0.2Cr0.8)1.5[Cr(CN)6]·15H2O Prussian blue analogue at low temperature has been investigated by means of synchrotron radiation-based X-ray absorption spectroscopy and X-ray magnetic circular dichroism. With the help of ligand field multiplet analysis we have been able to identify the oxidation states of the metallic cations present in the sample and their evolution with temperature. Our experiments reveal that the appearance of ferromagnetic order is triggered by the transformation of CrIII cations to CrII high-spin caused by a transfer of electrons from the Fe to the Cr resulting in an increase of the magnetic interactions within the (Cr, Cr) subla…

Self-assembled monolayers on a ferromagnetic permalloy surface.

Self-assembled monolayers (SAMs) are nowadays broadly used as surface protectors or modifiers and play a key role in many technological applications. This has motivated the study of their formation in all kind of materials; however, and despite the current interest in molecular spintronics, the study of SAMs on ferromagnetic surfaces remains almost unexplored. In this paper, we report for the first time a methodology for the formation of SAMs of n-alkylphosphonic acids on permalloy in ambient conditions. The formed monolayers have been fully characterized by means of contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, matrix assisted laser desorption ioniz…

MOKE magnetometry as a probe of surface magnetic impurities in electropolymerized magnetic thin films of the Prussian blue analogue Fe3[Cr(CN)6]2·15 H2O

A magneto-optical Kerr effect (MOKE) study has been performed on electrodeposited thin films of the Prussian blue analogue Fe3[Cr(CN)6]2·15H2O (1). This study reveals the onset of hysteretic magnetic signals at temperatures above 60 K, in contrast with magnetic susceptibility measurements which indicate a Curie temperature of 23 K for this ferromagnetic film. The origin of this discrepancy is due to the presence of amorphous iron oxide particles that accumulate in the surface of the material. This report illustrates the potential of MOKE magnetometry for the detection of surface chemical impurities that remain elusive using bulk magnetic techniques.

Spin polarization in electrodeposited thin films of the molecule-based magnetic semiconductor Cr5.5(CN)12·11.5H2O

The magnetoresistance (MR) effect of thin films of the Prussian Blue Analogue (PBA) Cr5.5(CN)12·11.5H2O, prepared by electrochemical deposition, has been measured using the standard two-point probe method. This molecule-based ferrimagnetic material, with a Tc = 240 K, exhibits MR up to 2% at 6 T and 200 K.

Photoinduced effects on the magnetic properties of the (Fe0.2Cr0.8)1.5[Cr(CN)6] Prussian blue analogue

International audience; One of the most attractive characteristics of some Prussian blue derivatives is the sensitivity of their magnetic properties to the irradiation with light. In this work photoinduced effects in the (Fe0.2Cr0.8)1.5[Cr(CN)6]·15H2O PBA have been studied by means of X-ray-based spectroscopies and magnetometry. It is found that the photosensitivity of this compound is mostly centred on the Fe cations: the exposure to green light induces a transfer of electrons from them to the Cr that provokes a reversal of the previously existing linkage isomerization and increases the elastic strain caused by the misfit of the unit cells of the Fe–NC–Cr and Cr–NC–Cr sublattices. The gree…