Short range Ordering, Nano-Structure and Unique Properties in Highly Concentrated Random Alloys

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In this project, we produced highly random systems mainly using a facing target-type sputtering. We studied the chemical, structural and morphological fluctuation, and the nano-granular particle formation in these systems as functions of deposition conditions and subsequent annealing, and their contibution to the magnetic and electrical properties. The following are the outlines.1) For Fe-Cr-N alloy films with good perpendicular anisotropy, the magnetic torque, ferromagnetic resonance and Mossbauer effect were observed to understand microscopic fluctuations in the magnetism and structures. The chemical bonding states were analyzed by the X-ray photoemission spectra. Combining these results with the X-ray diffraction and transmission electron microscope (TEM) observations, we can ascribe the perpendicular magnetic anisotropy to the complex structure of these films : the aciculate alpha-Fe crystallites growing perpendicular to the film plane are finely dispersed along the grain boundarie … More s of the columnar gamma- (FeCr) _4N crystals whose (200) reciprocal lattice vector is perpendicular to the film plane.2) The TEM micrographes, magnetization and electrical resistivity were observed for Co-C films. An amorphouslike Co-C phase is obtained when the substrate temperature, T_s is lower than 300ﾟC,while the Co particles of about 20nm in diameter are formed and surrouned by C (graphite) boundaries at T_s-350ﾟC,revealing a granular structure, and the phase separation is more pronounced at T_s>400ﾟC.A rather large magnetic coercive force of about 500 Oe is detected for Co_<50>C_<50> film made at T_s-350ﾟC.3) The meta-magnetic transition accompanying by the sign change of magnetoresistance was detected at low temperature for Eu-Fe random alloys produced by thermal evaporation. In Fe-Cu granular films produced by a ionized cluster beam method, moreover, the structure of Fe clusters in Cu matrices varies from fcc to bcc with increasing the Fe content and there is a hierarchy in the magnetic states of Fe clusters. Less