Preparation of Colloidal Sols: A magnetite colloid was prepared in alkaline solution according to the procedure published by Massart [11]. An aqueous solution containing 2.3 g (8.5 mmol) FeCl 3 ×6H 2 O in 4 mL H 2 O and 1.69 g (4.3 mmol) Fe(NH 4 ) 2 (SO 4 ) 2 in 1 mL of 2 M HCl, was added to 50 mL of 1 M (CH 3 ) 4 NOH×5H 2 O. The resulting black suspension was stirred for 1 h at room temperature and then sonicated in an ultrasonic bath for 1 h. The colloid was then centrifuged at 20 000 g for 1 h. The supernatant was decanted and the slurry resuspended in 20 mL water by sonication before being passed through a 0.2 mm pore cellulose nitrate membrane.A titanium dioxide sol was prepared by hydrolysis of titanium tetraisopropoxide under a nitrogen atmosphere following the procedure described by O'Regan et al. [12]. 25 mL of titanium tetraisopropoxide was mixed with 4 mL of isopropanol in a dropping-funnel under a nitrogen atmosphere. This mixture was added slowly over a period of 5 min to 150 mL of vigorously stirred double-distilled, deionized water in a 250 mL three-neck flask equipped with heater, thermometer and stirrer. Ten minutes after the final alkoxide addition, 1 mL of 69 % HNO 3 was added. The white hydrolysis mixture was then stirred for 8 h at 80 C to remove the isopropanol, filtered through a 0.2 mm pore cellulose nitrate membrane, and sonicated for 1 h to produce a stable colloidal solution with a bluish-white coloration.Preparation of the Composites and Method of Calcination: Typically, a sample of the sliced copolymer gel (ca. 5 mm thick) was added to the colloidal sol and left for the desired period of time. The colloid-loaded gels were removed, washed with water and allowed to dry in air. Thermogravimetric analysis (TGA) measurements were made using a NETZSCH STA 409EP machine. Samples were heated under air in an alumina crucible to a final temperature of 800 C at a rate of 5 K/min. Large samples of the mineralized gels were calcined by heating to a temperature of 450 or 500 C in a Carbolite furnace (type ELF11/6) at a heating rate of 1 C min ±1 .

We present measurements of the electrical conductivity of metallic nanowires which have been fabricated by chemical deposition of a thin continuous palladium film onto single DNA molecules to install electrical functionality. The DNA molecules have been positioned between macroscopic Au electrodes and are metallized afterwards. Low-resistance electrical interfacing was obtained by pinning the nanowires at the electrodes with electron-beam-induced carbon lines. The investigated nanowires exhibit ohmic transport behavior at room temperature. Their specific conductivity is only one order of magnitude below that of bulk palladium, confirming that DNA is an ideal template for the production of electric wires, which can be utilized for the bottom-up construction of miniaturized electrical circuits.

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Polycrystalline GdN thin films have been grown at room temperature with varying N2 pressure. By varying the nitrogen pressure during growth we alter the carrier concentrations of the films. Films grown at low nitrogen pressures display onset of magnetization at temperatures as high as 200 K and a resistivity of 0.3 mΩ cm, whereas films grown at high nitrogen pressures all show a Curie temperature very close to 70 K and resistivity ranges over 1–1000 Ω cm are observed. For all GdN films a peak in the resistivity occurs at TC.

This paper contains a summary of selected aspects of the epitaxial growth of rare‐earth nitride thin films and the recent progress achieved in this field. The discussion is focussed on GdN, SmN, EuN compounds grown by both pulsed laser deposition and molecular beam epitaxy on different substrates including YSZ (001), c‐plane (0001) AlN and GaN. While a N2 plasma cell is used as a nitrogen source for growing EuN, we take advantage of the catalytic breakdown of molecular nitrogen by rare‐earth atoms to grow GdN and SmN in the absence of activated N2. The structural, magnetic and transport properties of the thin films are assessed by reflection high‐energy electron diffraction, x‐ray diffraction, Hall Effect, temperature‐dependent magnetization and resistivity. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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We present a detailed study of the electronic structure of europium nitride (EuN), comparing spectroscopic data to the results of advanced electronic structure calculations. We demonstrate the epitaxial growth of EuN films, and show that in contrast to other rare-earth nitrides successful growth of EuN requires an activated nitrogen source. Synchrotron-based x-ray spectroscopy shows the samples contain predominantly Eu 3+ , but with a small and varying quantity of Eu 2+ that we associate with defects, most likely nitrogen vacancies. X-ray absorption and x-ray emission spectroscopies (XAS and XES) at the nitrogen K-edge are compared to several different theoretical models, namely LSDA+U (local spin density functional theory with Hubbard U corrections), dynamic mean field theory in the Hubbard-I approximation, and QSGW (quasiparticle self-consistent GW ) calculations. The DMFT and QSGW models capture better the density of conduction band states than LSDA+U . Only the Hubbard-I model contains a correct description of the Eu 4f atomic multiplets and locates their energies relative to the band states, and we see some evidence in XAS for hybridization between the conduction band and the the lowest lying 8 S multiplet. The Hubbard-I model is also in good agreement with purely atomic mutliplet calculations for the Eu M-edge XAS. LSDA+U and DMFT find a metallic ground state, while QSGW predicts a direct band gap at X for EuN of about 0.9 eV that matches closely an absorption edge seen in optical transmittance at 0.9 eV and a smaller indirect gap. Overall, the combination of theoretical methods and spectroscopies provides insights into the complex nature of the electronic structure of this material. The results imply that EuN is a narrow band-gap semiconductor that lies close to the metal-insulator boundary, where the close proximity to the Fermi level of an empty Eu 4f multiplet raises the possibility of tuning both the magnetic and electronic states in this system.