Solid State Phenomena Vol. 190

Abstract: We report electron transport properties of iron filled multiwalled carbon nanotubes (MWCNT) with outer diameters of 30 to 80 nm and lengths of 1 to 10 μm. Our study is combined with a structural investigation of the iron core using transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). It was found that high current densities of 1.8x10⁷ A/cm² increase the conductivity of the MWCNT by a factor of two at 300 K, while the Fe core disappears probably forming defect states in the carbon shells. The enhanced diffusion of iron is most probably the result of local heating of the iron followed by implantation of iron atoms in the nanotube layers.

Abstract: We have observed the formation of a thin buffer layer on the Fe/Cu interface at a temperature of 520 K. Mössbauer spectroscopy and magnetic studies reveal that the residual gases in the chamber (especially oxygen) play an important role in the ultra-thin interlayer formation. It was shown that the Cu2O buffer layer does not change the Pitsh orientation relationships during epitaxial growth of α-Fe (110) on Cu (001). Our analysis of the experimental results contradicts pseudomorphic growth and formation of γ-Fe on Cu (001).

Abstract: Co-Ti-O nanogranular films with different volume concentrations of a magnetic phase and Co/Ti-O layered structures with different numbers of layer pairs are studied by the magneto-optical Kerr effect. It is shown that, unlike the case of homogeneous metal films, the magneto-optical spectra of the nanogranular films exhibit resonance with a significant increase in the Kerr rotation angle in the wavelength range 500-700 nm. It is found that the Kerr rotation angle of the Co/Ti-O layer structures in the wavelength range 500-600 nm grows by an order of magnitude as compared to its value for ordinary Co films.

Abstract: The temperature dependent resistance and the noise characteristics of an individual multi-wall carbon nanotube (CNT) decorated with a finite number of magnetic nanocubes are investigated. We show that CNT is a highly sensitive bolometer and can enable measurements of magnetic resonance in a single nanoparticle.

Abstract: Results on the investigation of magnetic and magneto-optical properties of Fe/NML/Fe (NML: Mo, Ta) thin-film systems are presented. The examined samples were prepared by DC magnetron sputtering technique. The hysteresis loops and spectral dependencies of the transverse Kerr effect (TKE) were measured employing the magneto-optical magnetometer and the magneto-optical spectrometer, respectively. The saturation field of the examined trilayers was revealed to oscillate as a function of the NML layer thickness, and the period of these oscillations to depend on the Fe layer thickness. The TKE spectra of the studied systems were found to be identical but the TKE values depend on the thickness of both Fe and Mo, Ta layers.

Abstract: The characteristics of the periodic fine structure in domain walls in oblique-evaporated films of quantum-well (QW) thickness with an easy-magnetization axis inclined with respect to the normal to the film plane has been studied. It is pointed out that the self-organization of domain structures is related to the quantum character of the cooperative phenomenon of ferromagnetism [. The spectrum of magnetoelastic waves has been calculated for films of iron type.

Abstract: Removed due to double publication by the author The original was published: High-density nickel nanowire arrays for data storage applications 2012 J. Phys.: Conf. Ser. 345 012011 http://iopscience.iop.org/1742-6596/345/1/012011

Abstract: Pronounced optical-and bias-current-sensitive features of the transport properties of a Fe/SiO₂/p-Si hybrid structure in planar geometry at temperature variation are investigated. Comparative analysis of two Fe/SiO₂/p-Si samples, one with a continuous Fe film and the other with two electrodes formed from a Fe layer and separated by a micron gap, shows that these features are due to the MIS transition with a Schottky barrier near the interface between SiO₂ and p-Si. Resistance of such a MIS transition depends exponentially on temperature and bias. In the structure with a continuous ferromagnetic film, the competition between conductivities of the MIS transition and the Fe layer results in the effect of current channel switching between the Fe layer and a semiconductor substrate. Within certain limits, this process can be controlled by a bias current and optical radiation. The mechanism of the optical effect is photogeneration of electron-hole pairs in the semiconductor substrate near its boundary with SiO₂ layer.

Abstract: A first-order metamagnetic transition from antiferromagnetic to ferromagnetic state in La (Fe0.88Al0.12-xSix) compounds was investigated using Mossbauer effect. The exchange-related clusters in the ferromagnetic and antiferromagnetic state are shown to exist. The influence of Si on magnetic structure is observed.

Abstract: The results of X-ray diffraction, complex in-field (up to 9 T) and temperature (5300 К) Mössbauer and magnetometric studies of the ordered Fe₆₅Al_35-хM_х (M=Ga, B; x=0,5,10) and Fe_65-хV_xAl₃₅ (x=5,10) alloys are presented. Analysis of the magnetometry studies shows that the systems Fe₆₅Al₃₅ и Fe₆₅Al_35-хGa_х (x=5, 10) are characterized by two different magnetic states with essentially distinguishing hysteresis loops and AC susceptibility values. The temperature and external magnetic field values inducing the transition from one magnetic state to another are higher in the Ga-doped alloys than in the reference Fe₆₅Al₃₅ alloy. The boron addition transforms the magnetic state of the initial alloy Fe₆₅Al₃₅ into a ferromagnetic one exhibiting high magnetic characteristics. Substitution of V for Fe in the ternary alloys Fe_65-хV_xAl₃₅ results in reduction of magnetic characteristics and collapsing of ⁵⁷Fe hyperfine magnetic filed.