The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform

K Uebayashi - One of the best experts on this subject based on the ideXlab platform.

  • structure and magnetism of 3d and 4d Transition Metal Alloys tt t mn fe and t rh pd with cuau i type ordered structure
    Journal of Alloys and Compounds, 2006
    Co-Authors: H Yamada, H Shimizu, K Yamamoto, K Uebayashi
    Abstract:

    First-principle band calculations of 3d and 4d Transition-Metal Alloys FeRh, FePd, MnRh and MnPd with CuAu-I type ordered structure are carried out by a linear muffin-tin orbital method within an atomic sphere approximation, where a generalized gradient correction for exchange-correlation potential is taken into account. Total energies for paramagnetic, ferromagnetic and three kinds of antiferromagnetic states are estimated as a function of lattice constants a and c. Observed lattice constants and spin structures of these Alloys are well described by the present calculations. It is shown that the paramagnetic (non-magnetic) state without local magnetic moments is not stable in CsCl-type structure for these Alloys.

S.a. Nikitin - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic properties of amorphous rare-earth – 3d-Transition-Metal Alloys
    Physics-Uspekhi, 1997
    Co-Authors: A.s. Andreenko, S.a. Nikitin
    Abstract:

    Work on the magnetic properties of amorphous rare-earth–3d-Transition-Metal Alloys is reviewed using current theoretical models to account for the experimental data available. The exchange interaction and random magnetic anisotropy are shown to dominate the magnetization and magnetization reversal processes. Some new phenomena related to the effect of induced magnetic anisotropy on magnetization processes are considered. The results on the magnetoelastic properties of rare-earth Alloys are systematized. The dependence of the exchange integrals on the interatomic separation is determined. It is shown that pressure significantly affects the magnetic structure and phase Transitions in these magnetic materials.

H Yamada - One of the best experts on this subject based on the ideXlab platform.

  • structure and magnetism of 3d and 4d Transition Metal Alloys tt t mn fe and t rh pd with cuau i type ordered structure
    Journal of Alloys and Compounds, 2006
    Co-Authors: H Yamada, H Shimizu, K Yamamoto, K Uebayashi
    Abstract:

    First-principle band calculations of 3d and 4d Transition-Metal Alloys FeRh, FePd, MnRh and MnPd with CuAu-I type ordered structure are carried out by a linear muffin-tin orbital method within an atomic sphere approximation, where a generalized gradient correction for exchange-correlation potential is taken into account. Total energies for paramagnetic, ferromagnetic and three kinds of antiferromagnetic states are estimated as a function of lattice constants a and c. Observed lattice constants and spin structures of these Alloys are well described by the present calculations. It is shown that the paramagnetic (non-magnetic) state without local magnetic moments is not stable in CsCl-type structure for these Alloys.

Czesław Kapusta - One of the best experts on this subject based on the ideXlab platform.

  • NMR spectroscopy of rare earth–3d Transition Metal Alloys
    Journal of Alloys and Compounds, 1998
    Co-Authors: Czesław Kapusta
    Abstract:

    Recent nuclear magnetic resonance studies of magnetically ordered rare earth–3d Transition Metal Alloys are reviewed. Selected experimental results for rare earth NMR of RETM2 Laves phases as well as RE2TM14B and interstitially modified RE2TM17Ax (A=N,C,H) materials for permanent magnet applications are surveyed. An analysis of the hyperfine parameters obtained from NMR experiments is presented and their relation to the physical properties of individual atomic sites is discussed. In particular, information from hyperfine fields about the influence of light interstitial atoms on the RE–TM magnetic coupling is analysed and compared to the results of magnetisation and neutron measurements. The relation of quadrupole splitting to the spectroscopic state of the rare earth, the magnetic structure and the individual site contributions to the magnetocrystalline anisotropy is analysed. The applicability of NMR to the study of multiphase magnetic materials for technology is briefly discussed

M. H. Loretto - One of the best experts on this subject based on the ideXlab platform.

  • Stability and decomposition mechanisms of supersaturated solid solutions in rapidly solidified aluminium–Transition Metal Alloys
    Materials Science and Technology, 1996
    Co-Authors: X. D. Zhang, M. H. Loretto
    Abstract:

    AbstractThe annealing of supersaturated solid solutions has been studied in a number of rapidly solidified AI-Transition Metal Alloys using transmission electron microscopy. Two very different decomposition processes have been found. The first involves the generation and migration of dislocation networks which provide short circuit diffusion paths to the grain boundaries for the solute atoms, where they precipitate as the equilibrium phase. Typical examples are Al–Mo and Al–V The second mechanism involves the precipitation of metastable quasicrystals in the grains before the equilibrium phase is formed, also within the grains. This process has been observed in Al–Cr and Al–Fe Alloys. The different mechanisms are discussed in terms of the ability to generate dislocations and the stability of quasicrystal precipitates in Al–Transition Metal Alloys. Stable supersaturated solid solutions containing quasicrystals exhibit strong strengthening behaviour. The significance of these observations is discussed in ter...

  • Structure and stability of the precipitates in melt spun ternary Al-Transition-Metal Alloys
    Acta Metallurgica Et Materialia, 1993
    Co-Authors: X. D. Zhang, Y.j. Bi, M. H. Loretto
    Abstract:

    Abstract The decomposition of supersaturated solid solution of ternary, melt spun Al-Transition-Metal Alloys has been examined using analytical transmission electron microscopy. It has been found that the presence of small amounts of iron in AlV, AlMo and AlCr Alloys can give rise to a fine dispersion of P-phase precipitate in the grain centres. It has been shown that the P-phase is quasicrystalline phase and has an orientation relationship with Al matrix as: i2|〈001〉Al, 〈τ2τ1〉Al, i3|〈111〉Al, 〈τ210〉Al; i5|〈τ10〉Al, τ = (1 + √5)/2. The stability of quasicrystals is significantly improved by the presence of iron in A1-Transition-Metal Alloys. The effect of iron on stabilising the quasicrystal precipitates is believed to be due to the fact that iron replaces the oversized Transition Metal (TM) atoms V, Cr and Mo in the smaller TM sites, resulting in a reduction of structural stress of quasicrystalline phase. The significance of these observations on the structure and stability of quasicrystal precipitates is discussed in terms of the development of high temperature dispersion strengthening Al-based Alloys with Transition Metals.