FABRICATION OF MICRON SCALE MAGNETIC NICKEL FEATURES BY SELECTIVE AREA ORGANOMETALLIC CHEMICAL VAPOR DEPOSITION

We demonstrate that it is possible to deposit a wide range of magnetic features, using photo-assisted and electron radiation induced selective area organometallic chemical vapor deposition. Large arrays of identical micron to nano scale Ni features were deposited by these methods. Their magnetic properties were studied by alternating gradient force magnetometry as well as magnetic force microscopy. Our morphological and magnetic measurements show that the structures are spatially well defined, and the magnetic properties are related to the structural shapes of the features

Optical properties of boron carbide (B\u3csub\u3e5\u3c/sub\u3eC) thin films fabricated by plasma-enhanced chemical-vapor deposition

Variable angle of incidence spectroscopic ellipsometry was used to determine the optical constants near the band edge of boron carbide (B5C) thin films deposited on glass and n-type Si(111) via plasma-enhanced chemical-vapor deposition. The index of refraction n, the extinction coefficient k, and the absorption coefficient are reported in the photon energy spectrum between 1.24 and 4 eV. Ellipsometry analysis of B5C films on silicon indicates a graded material, while the optical constants of B5C on glass are homogeneous. Line shape analyses of absorption data for the films on glass indicate an indirect transition at approximately 0.75 eV and a direct transition at about 1.5 eV. ©1996 American Institute of Physics

The influence of enhanced surface magnetism on finite-size scaling

The thickness-dependent spin-polarized electronic structure of strained ultrathin and thin films of Gd has been investigated. The surface magnetic structure dominates the magnetic ordering of the ultrathin Gd films. With decreasing thickness some bulk bands exhibit increasingly more passive magnetic behavior. These bulk bands resemble a paramagnet over an increasing volume of the bulk Brillouin zone with decreasing film thickness

Electronic structure and Curie temperature of YFe\u3csub\u3e12-x\u3c/sub\u3eMo\u3csub\u3ex\u3c/sub\u3eN\u3csub\u3e\u3ci\u3ey\u3c/i\u3e\u3c/sub\u3e compounds

The electronic structures of YFe12-xMoxNy , where x=1.0, 2.0 and y=0, 0.7, have been studied with photoemission and spin-polarized calculations. The peak near the Fermi level in the energy distribution curves (EDC) becomes successively broader with larger Mo concentration. The features in the calculated density of state at 1.3 and 2.7 eV are not readily seen in the EDC, and this may be due to lifetime effects in these compounds. Finally, changes in Curie temperature (Tc) with the change of N or Mo concentration are compared with prediction of the theory of Mohn and Wohlfarth. Reasonable agreement is obtained in the N case but not in the Mo case, the latter most likely due to hybridization of Fe and Mo d bands

Electronic structures and Curie temperatures of iron-based rare-earth permanent-magnet compounds

The modification of the electronic structures of Sm2Fe17-xAlxNy, NdFe11TiNy, and YFe12-xMox upon alloying and nitriding are examined with self-consistent spin-polarized calculations and soft-x-ray photoemission measurements between 18 and 135 eV. The changes in the Curie temperature Tc with substitutional modifications and nitrogen addition are modeled with self-consistent spin-polarized electronic structure calculations and the spin-fluctuation theory of Mohn and Wohlfarth which relates the electronic structure to Tc. The calculations show that the spin-summed density of states at the Fermi energy is related to Tc. The photoemission spectra are dominated by the Fe 3d electrons within 3 eV of the Fermi energy in agreement with calculations. Changes in the density of states at the Fermi energy for interstitial and and substitutional modification compare well with calculations. Using photoemission results with experimental magnetic moments for the substitutional modification of the compound Sm2Fe17-xAlx, the spin-fluctuation theory predicts a change in Tc in agreement with the measured change in Tc. Spin-resolved photoemission spectra for c-axis oriented Sm2Fe17N2.6 with magnetization perpendicular to the surface are presented and compared to theoretical calculations

Electronic structure of Sm\u3csub\u3e2\u3c/sub\u3eFe\u3csub\u3e17\u3c/sub\u3eN\u3csub\u3ex\u3c/sub\u3e compounds

Sm2Fe17Nx is of considerable current interest as a permanent-magnet material because of its enhanced Curie temperature and uniaxial anisotropy. The electronic structures of Sm2Fe17Nx for x=0 and x~2.6 have been studied with photoemission and spin-polarized calculations. The materials are prepared by arc melting and nitrogen is introduced by ion implantation. The nitrogen concentration is quantified with Auger electron spectroscopy. The Sm 4f electrons with binding energies between 6 and 10 eV are investigated with resonant photoemission using photon energies near 140 eV. The major features of ultra-violet photoemission spectra include the Fe 3d band with a strong peak at 0.8 eV and a small peak at 2.9 eV below the Fermi energy which agree quite well with the theoretical density of states calculation. The modification of the electronic structure with nitrogen concentration is studied to understand the effect of nitrogen addition on the magnetic properties. Journal of Applied Physics is copyrighted by The American Institute of Physics