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Two thin film deposition routes were studied for the growth of high quality single crystalline Ru (0001) epitaxial films on c-Al2O3 substrates using radio frequency-magnetron sputtering. Such films are very important as buffer layers for the deposition of epitaxial non-collinear antiferromagnetic Mn3X films. The first route involved depositing Ru at 700 °C, leading to a smooth 30 nm thick film. Although, high resolution x-ray diffraction revealed twinned Ru film orientations, in situ post-annealing eliminated one orientation, leaving the film orientation aligned with the substrate, with no in-plane lattice rotation and a large lattice mismatch (13.6%). The second route involved the deposition of Ru at room temperature followed by in situ post-annealing at 700 °C. Transmission electron microscopy confirmed a very high quality of these films, free of crystal twinning, and a 30° in-plane lattice rotation relative to the substrate, resulting in a small in-plane lattice mismatch of –1.6%. X-ray reflectivity demonstrated smooth surfaces for films down to 7 nm thickness. 30 nm thick high quality single-crystalline Mn3Ga and Mn3Sn films were grown on top of the Ru buffer deposited using the second route as a first step to realize Mn3X films for antiferromagnetic spintronics applications. [ABSTRACT FROM AUTHOR]

We fabricated NiFe2O4 thin films on MgAl2O4 (001) substrates by reactive dc magnetron co-sputtering in a pure oxygen atmosphere at different substrate temperatures. The film properties were investigated by various techniques with a focus on their structure, surface topography, magnetic characteristics, and transport properties. Structural analysis revealed a good crystallization with epitaxial growth and low roughness and a similar quality as in films grown by pulsed laser deposition. Electrical conductivity measurements showed high room temperature resistivity (12Ωm), but low activation energy, indicating an extrinsic transport mechanism. A band gap of about 1.55 eV was found by optical spectroscopy. Detailed x-ray spectroscopy studies confirmed the samples to be ferrimagnetic with fully compensated Fe moments. By comparison with multiplet calculations of the spectra, we found that the cation valencies are to a large extent Ni2+ and Fe3+. [ABSTRACT FROM AUTHOR]

Magnetron sputtered thin Co–Mn–Sb films were investigated with respect to their element-specific magnetic properties. Stochiometric Co1Mn1Sb1 crystallized in the C1b structure has been predicted to be half-metallic and is therefore of interest for spintronic applications. It should show a characteristic antiferromagnetic coupling of the Mn and Co magnetic moments and a transition temperature TC of about 480 K. Although the observed transition temperature of our 20 nm thick Co32.4Mn33.7Sb33.8, Co37.7Mn34.1Sb28.2, and Co43.2Mn32.6Sb24.2 films is in quite good agreement with the expected value, we found a ferromagnetic coupling of the Mn and Co magnetic moments which indicates that the films do not crystallize in the C1b structure and are probably not fully spin polarized. The ratio of the Co and Mn moments does not change up to the transition temperature and the temperature dependence of the magnetic moments can be well described by the mean-field theory. [ABSTRACT FROM AUTHOR]

The Heusler alloy Co2MnSi with theoretically predicted 100% spin polarization has been successfully implemented in Co2MnSi/AlOx/Co7Fe3 magnetic tunnel junctions recently. Here we investigated 100 nm thick Co2MnSi films grown on a vanadium buffer and capped by a thin alumina film. This stack is similar to the lower electrode including the tunneling barrier of magnetic tunnel junctions. By soft x-ray absorption spectroscopy and magnetic circular dichroism in fluorescence and total electron yield detection we determined differences between the chemical and magnetic properties of the Co2MnSi thin films and the Co2MnSi/AlOx interface. Whereas MnO was formed directly at the interface during plasma oxidation of the Al layer, the interfacial Co was not oxidized and its x-ray absorption line shape at the L2,3 edge was similar to the line shape of bulk Co2MnSi. The atomically ordered bulk Co2MnSi showed characteristic differences in the x-ray absorption spectra in comparison with the disordered samples: in the ordered state of the bulk both, Co and Mn, showed additional shoulders about 4 eV above the L2,3 resonances, a large circular dichroism, and a pronounced x-ray absorption near edge fine structure. The same was found for interfacial Co, whereas for interfacial Mn these features were masked by the characteristic absorption multiplet structure of MnO right at the interface which also resulted in a strong reduction of the interfacial Mn moment in annealed samples. [ABSTRACT FROM AUTHOR]

Presents the results of an ultrahigh vacuum scanning-tunneling-microscopy study of large scale mass transport in current carrying metal films. Factors that affect the mass transport process in real materials; Primary driving forces that can bias atomic motion in metal films; Electromigration results from the electrical driving force.

Presents a study that discussed the reliability of scanning tunneling microscopy (STM) images of rough surfaces of polycrystalline thin films. Details of the etching procedure; Estimation of the tip shape of the rough surfaces; Comparison of the images from STM and transmission electron microscopy.

Presents information on a study that investigated the resistance behavior of NiCr/CuNi(Mn)/NiCr film systems in comparison with CuNi(Mn) and NiCr single films during annealing. Methodology of the study; Results and discussion on the study.

Magneto-optical and electronic properties of the Co2FeSi Heusler compound were studied by polar Kerr magneto-optical spectroscopy and ab-initio calculations. The thin-film samples were grown by dc/rf magnetron co-sputtering on MgO(100) substrates. A Cr seed layer was deposited prior to the Co2FeSi layer to achieve its epitaxial growth. The magneto-optical spectroscopy was carried out using generalized magneto-optical ellipsometry with rotating analyzer in the photon energy range from 1.4 to 5.5 eV with an applied magnetic field of up to 1.2T. The polar Kerr spectra showed a smooth spectral behavior up to 5.5 eV indicating nearly free charge carriers. Experimental data were compared with ab-initio calculations based on density functional theory employing the full-potential linearized augmented plane wave method. [ABSTRACT FROM AUTHOR]

Analyzes the application of scanning tunneling microscopy (STM) for a quantitative evaluation of roughnesses and mean island sizes of polycrystalline thin films. Main problems of STM imaging of rough surfaces; Details on the experiment; Obstacle in the evaluation of island sizes.

In concepts for logic circuits using hysteretic magnetoresistive effects, one gains advantages of magnetic thin-film elements, e.g., nonvolatility, radiation hardness and nondestructive readout. The requirements concerning reproducibility of resistance and magnetoresistance, however, are much more stringent than for memory applications. Using experimental data of magnetic logic circuits, we show that the variances of resistance and magnetoresistance, and the amplitude of the magnetoresistance, determine the yield of working logic gates. The current magnetoresistance of 75% for CoFeB/Al2O3 junctions is close to the minimum required value. More than 250% obtained with MgO barriers, however, will allow a fault tolerant production. [ABSTRACT FROM AUTHOR]

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010. [ABSTRACT FROM PUBLISHER]

Transverse magnetothermoelectric effects are studied in Permalloy thin films grown on MgO and GaAs substrates and compared to those grown on suspended SiNx membranes. The transverse voltage along platinum strips patterned on top of the Permalloy films is measured versus the external magnetic field as a function of the angle and temperature gradients. After the identification of the contribution of the planar and anomalous Nernst effects, we find an upper limit for the transverse spin Seebeck effect, which is several orders of magnitude smaller than previously reported. [ABSTRACT FROM AUTHOR]

Abstract: Deposition of metals and alloys was demonstrated using thermal chemical vapor deposition starting from commercially available precursors in the absence of molecular hydrogen. The adopted chemical strategy relies solely on the selective reactivity of alcohols with metal complexes at deposition temperature. In this report, particular interest was given to the growth of nickel and silver. This process allows the optimization of the growth of single hcp and fcc phases of nickel starting from Ni(acac)2, whereas several silver precursors allow the deposition of the fcc crystalline structure of silver. Steady growth kinetics, without incubation time, was noticed for all investigated precursors. The electrical conductivity of hcp-Ni, fcc-Ni and fcc-Ag shows the typical decay to the bulk value with increased film thickness, and the temperature resistivity coefficients are similar to the corresponding bulk material. [Copyright &y& Elsevier]