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We have measured the valence spectra of K-doped C60 monolayer films adsorbed on Si(0 0 1)-(2×1) and Si(1 1 1)-(7×7) surfaces. No density of states is observed at the Fermi level for the undoped C60 monolayer films on both Si surfaces. After a small K doping, a density of states is clearly observed at the Fermi level on a Si(0 0 1)-(2×1) surface. On the other hand, no density of states is observed at the Fermi level at any amount of K doping on a Si(1 1 1)-(7×7) surface. The difference observed on both Si surfaces indicates that the symmetry of C60 molecules is almost the same as that in solid phase on a Si(0 0 1)-(2×1) surface, and is broken due to a stronger C60-substrate and/or C60–C60 interaction on the Si(1 1 1)-(7×7) one. [Copyright &y& Elsevier]

In this study, we prepared Q-carbon by adjusting the sp 3 content in diamond-like carbon (DLC) films and the laser energy density of pulsed laser annealing (PLA). The amorphous DLC films were fabricated on sapphire Al 2 O 3 (0001) substrates using a pulsed laser deposition technique with a KrF excimer laser (λ = 248 nm). The sp3 content in the films varied between 20% and 42% by changing the laser energy density. Subsequently, PLA was performed on the DLC films by using the KrF excimer laser with energy densities between 0.5 and 1.2 J/cm2. The prepared films were characterized using scanning electron microscopy, Raman spectroscopy, and magnetization measurements. Consequently, for the combination of 20% sp 3 content and laser density of 1.0 J/cm2, as well as 42% sp 3 and 0.5 J/cm2, the films showed the characteristic features of Q-carbon: filamentary nanostructures, the presence of a T band in the Raman spectrum, room-temperature ferromagnetic behavior, and ∼80% sp 3 content. The results indicate that Q-carbon can be obtained by using a proper combination of sp 3 content in DLC films and an appropriate PLA energy density. This study provides important guidance for establishing a preparation method for Q-carbon. Image 1 [ABSTRACT FROM AUTHOR]

We present multilayer formation via spinodal decomposition in rutile TiO 2 -VO 2 (TVO) epitaxial films on sapphire substrates. (001)- and (101)-oriented TVO solid-solution films are grown epitaxially on TiO 2 /Al 2 O 3 using a pulsed laser deposition technique and annealed inside the spinodal region. X-ray diffraction measurements and scanning transmission electron microscopy (STEM) observations show that the films are phase-separated along the [001] direction and lamellar structures are formed in a parallel or slanted direction to the sapphire substrates depending on the film orientation. The results indicate the multilayer formation via spinodal decomposition in the TVO films. STEM investigations also reveal a relatively high Ti concentration in the decomposed phases, reflecting the influence of lattice deformation on the phase decomposition in the films. Our work shows that spinodal decomposition is a promising approach for the formation of a multilayer structure in TVO films and helps deepen understanding the spinodal decomposition in TVO system. [ABSTRACT FROM AUTHOR]

We have investigated the electronic states and spin polarization of half-metallic ferromagnet CrO 2 (100) epitaxial films by bulk-sensitive spin-resolved photoemission spectroscopy with a focus on non-quasiparticle (NQP) states derived from electron-magnon interactions. We found that the averaged values of the spin polarization are approximately 100% and 40% at 40 K and 300 K, respectively. This is consistent with the previously reported result [H. Fujiwara et al., Appl. Phys. Lett. 106 , 202404 (2015).]. At 100 K, peculiar spin depolarization was observed at the Fermi level ( E F ), which is supported by theoretical calculations predicting NQP states. This suggests the possible appearance of NQP states in CrO 2 . We also compare the temperature dependence of our spin polarizations with that of the magnetization. [ABSTRACT FROM AUTHOR]

The effects of aliovalent dopants on the kinetics of spinodal decomposition in a rutile-type TiO 2 -VO 2 system were studied by means of x-ray diffraction and transmission electron microscopy. In this study, as-prepared polycrystalline samples were annealed at 673 k inside the spinodal. For undoped samples, phase decomposition occurred along the [001] direction, and a lamellar structure formed on the nanometer length scale. The phase decomposition kinetics in this system were sensitive to the type of aliovalent dopant; the decomposition rate in a sample doped with Al 2 O 3 was more than one order of magnitude higher than a sample doped with Nb 2 O 5 . These observations could be explained on the basis of the premise that cation interstitial mobility is greater than cation vacancy mobility. The obtained results are consistent with those for a TiO 2 -SnO 2 system, indicating that phase separation in both rutile-type oxide systems can be interpreted through a common framework. [ABSTRACT FROM AUTHOR]

Abstract: We have used photoelectron emission microscopy (PEEM) and X-ray magnetic circular dichroism (XMCD) to study the effect of thin film thickness on the magnetic domain formation in La0.6Sr0.4MnO3 samples that were epitaxially grown on stepped SrTiO3 (001) substrates. The magnetic image exhibited a stripe structure elongated along the step direction, irrespective of film thickness, suggesting that uniaxial magnetic anisotropy induced by step-and-terrace structures plays an important role in the magnetic domain formation. Additional domains evolved gradually with increasing film thickness. In these domains, the direction of magnetization differed from the step direction due to biaxial magneto-crystalline anisotropy. The evolution of additional magnetic domains with increasing film thickness implies that a competition exists between the two anisotropies in LSMO films. [Copyright &y& Elsevier]

The surface states dispersion of the Gd-induced one-dimensional chain structure on Si(1 1 1) with a 5×2 periodicity was determined by means of angle-resolved photoelectron spectroscopy(ARPES). At least three surface states are observed at the binding energy of around 1–2 eV. The dispersions of these surface states resemble those of the alkali-earth metal-induced Si(1 1 1) 5×2 surface suggesting a similar surface atomic structure. Besides these three prominent surface states, another state with very weak intensity is also observed near the Fermi level; this is different from the alkali-earth metal-induced 5×2 surface in which the surface electronic state is semiconducting. [Copyright &y& Elsevier]