Finite-temperature magnetism of Ni monolayers: Interplay between flips and amplitude fluctuations of the local moments Article uri icon

abstract

  • The temperature dependence of the magnetization and spin fluctuation energies in Ni bulk and monolayers are determined in the framework of a functional-integral itinerant-electron theory. The electronic structure is obtained in the static approximation from a realistic spd-band model by using a real-space recursive expansion of the local Green%27s functions. The statistical averages of the spin fluctuations are performed by treating disorder within the coherent potential approximation. Results for the magnetization M(T) and spin fluctuation energies of (001) fcc monolayers are presented for several values of the nearest-neighbor distance. Local environmental effects are discussed by comparison with bulk results. An interesting transition from simple spin flips to amplitude fluctuations of the local exchange fields is revealed as a function of dimensionality and bond length. Important qualitative differences in the spin fluctuation energies of Ni are observed as compared to Fe, which reflect different mechanisms of the dominant spin excitations in these itinerant-electron ferromagnets. The effects of sp electrons and sp-d hybridizations are discussed. © 2012 American Physical Society.
  • The temperature dependence of the magnetization and spin fluctuation energies in Ni bulk and monolayers are determined in the framework of a functional-integral itinerant-electron theory. The electronic structure is obtained in the static approximation from a realistic spd-band model by using a real-space recursive expansion of the local Green's functions. The statistical averages of the spin fluctuations are performed by treating disorder within the coherent potential approximation. Results for the magnetization M(T) and spin fluctuation energies of (001) fcc monolayers are presented for several values of the nearest-neighbor distance. Local environmental effects are discussed by comparison with bulk results. An interesting transition from simple spin flips to amplitude fluctuations of the local exchange fields is revealed as a function of dimensionality and bond length. Important qualitative differences in the spin fluctuation energies of Ni are observed as compared to Fe, which reflect different mechanisms of the dominant spin excitations in these itinerant-electron ferromagnets. The effects of sp electrons and sp-d hybridizations are discussed. © 2012 American Physical Society.

publication date

  • 2012-01-01