Composition range of binary amorphous alloys

We have studied a number of binary metal-metal and metalloid alloy systems made by a single vapor-quench method under very consistent conditions. In each case, amorphous alloys are found in one continuous composition range (xmin≤x≤xmax) regardless of the number of eutectic points in the equilibrium phase diagrams. It is found that the atomic size difference is the single most important factor in the quantitative determination of the composition range

Composition range of binary amorphous alloys

We have studied a number of binary metal-metal and metalloid alloy systems made by a single vapor-quench method under very consistent conditions. In each case, amorphous alloys are found in one continuous composition range (xmin≤x≤xmax) regardless of the number of eutectic points in the equilibrium phase diagrams. It is found that the atomic size difference is the single most important factor in the quantitative determination of the composition range

Mössbauer study of sputtered Fe-Ti alloys with wide composition range

FexTi100-x alloys over a wide composition range has been made by high-rate sputtering and studied by 57Fe Mössbauer spectroscopy. Samples with 30 ≤ x ≤ 80 are amorphous whereas samples with x ≥ 85 are metastable crystalline bcc alloys. Large differences in magnetic properties (e.g., Tc) and hyperfine interactions (Heff, isomer shift) are found between the amorphous and bcc alloys. Comparison of FeTi and Fe2Ti in amorphous and crystalline states show that the short-range order in the amorphous state has no resemblence to that of the crystalline compounds

Epitaxial growth and magnetic properties of Cr-doped AlN thin films

Cr-doped AlN thin films were epitaxially grown on Al2O3(001) substrates at low temperature by reactive magnetron sputtering,and their magnetic properties were investigated. Extensive x-ray diffraction studies indicated that the films have a wurtzite-type hexagonal structure and are (001) oriented, with an epitaxial relationship of the [100] direction of the films along the [110] direction of Al2O3. The c axis lattice parameter of the films showed a linear dependence on the Cr concentration for Cr concentrations below 0.15. Room temperature ferromagnetism was observed, and the magnetic properties showed strong dependence on the Cr concentration over a wide range

Epitaxial growth and magnetic properties of Cr-doped AlN thin films

Cr-doped AlN thin films were epitaxially grown on Al2O3(001) substrates at low temperature by reactive magnetron sputtering,and their magnetic properties were investigated. Extensive x-ray diffraction studies indicated that the films have a wurtzite-type hexagonal structure and are (001) oriented, with an epitaxial relationship of the [100] direction of the films along the [110] direction of Al2O3. The c axis lattice parameter of the films showed a linear dependence on the Cr concentration for Cr concentrations below 0.15. Room temperature ferromagnetism was observed, and the magnetic properties showed strong dependence on the Cr concentration over a wide range

Incommensurate superlattice and 90° twist boundaries in the superconducting phase of Bi-Sr-Ca-Cu-O

We have observed an incommensurate superlattice structure in the Bi-Sr-Ca-Cu-O system using electron diffraction. The wave vector of the superlattice, q=(0,1/4.7,1), has an incommensurate component along the b axis and a commensurate component along the c axis. Twist boundaries perpendicular to the c axis, across which the crystallographic a and b axes are rotated 90°, are commonly observed in this system

High resolution electron microscopy and nano-probe study of CoSm/Cr films

The crystal structure of the crystallites in CoSm thin films deposited on Cr underlayer was studied by nanodiffraction and high resolution electron microscopy (HREM). It was found that the crystallites have a closed-packed structure. Some nanodiffraction patterns taken from different crystallites using a two nanometer probe can be indexed by two layer stacking AB (HCP structure), three layer stacking ABC (FCC structure), and four layer stacking ABAC (double hexagonal structure), suggesting that a particular local stacking mode could exist. [112-0] HREM images confirmed that stacking sequence changes within one crystallite. In local regions, random stacking, and unit cells of two layer stacking ABAC were found

Effect of Au spacer layer on \u3ci\u3eL\u3c/i\u3e1\u3csub\u3e0\u3c/sub\u3e phase ordering temperature of CoPt thin films

We have studied the effect of Au on the ordering temperature of CoPt films. The coercivity of the CoPt multilayer with 2 nm Au inserted is around 5 kOe after annealing at 400 °C. This ordering temperature is about 200 °C lower than that of a pure CoPt film. Crystallographical analysis using x-ray diffraction has also revealed that the lattice constant is drastically changed around the same temperature, which is related to the formation of the L10-ordered structure. Thus, the Au plays an important role in reducing the ordering temperature

Effect of Au spacer layer on \u3ci\u3eL\u3c/i\u3e1\u3csub\u3e0\u3c/sub\u3e phase ordering temperature of CoPt thin films

We have studied the effect of Au on the ordering temperature of CoPt films. The coercivity of the CoPt multilayer with 2 nm Au inserted is around 5 kOe after annealing at 400 °C. This ordering temperature is about 200 °C lower than that of a pure CoPt film. Crystallographical analysis using x-ray diffraction has also revealed that the lattice constant is drastically changed around the same temperature, which is related to the formation of the L10-ordered structure. Thus, the Au plays an important role in reducing the ordering temperature

Nanostructured FePt:B\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e thin films with perpendicular magnetic anisotropy

FePt/B2O3 multilayers were deposited by magnetron sputtering onto 7059 glass substrates. By annealing the as-deposited films at 550 °C, nanostructured FePt:B2O3 films consisting of FePt grains with L10 structure, embedded in a glassy B2O3 matrix, were obtained. The c axes of the FePt grains can be made to align with the film normal direction, which results in a perpendicular anisotropy constant of 3.5×107 erg/cc. The films remain layered structures after annealing when the B2O3 layer thickness exceeds 16 Å. The nanostructure of the films was investigated by transmission electron microscopy. The coercivities and the average grain sizes of the films are dependent on the B2O3concentrations, with coercivities varying from 4 to 12 kOe, while average grain sizes vary from 4 to 17 nm. Strong perpendicular anisotropy, adjustable coercivity, and fine grain size suggest this nanocomposite system might have significant potential as recording media at extremely high areal density