کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1564263 999638 2006 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Calculation of orbital polarization effects in small Co clusters
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مکانیک محاسباتی
پیش نمایش صفحه اول مقاله
Calculation of orbital polarization effects in small Co clusters
چکیده انگلیسی

The effects of orbital polarizations on the magnetic properties of small Co clusters are investigated in the framework of a self-consistent electronic model Hamiltonian including local Coulomb interactions at three different levels of approximation: (i) full orbital dependence of the direct and exchange Coulomb interactions Umm′ and Jmm′ as given by atomic symmetry, (ii) orbital-independent interactions U=Umm′¯andJ=Jmm′¯, and (iii) orbital polarization (OP) approximation of the form HOP=-(B/2)∑iLˆiδ2, where Lˆiδ refers to the orbital momentum operator at atom i and B to the Racah coefficient. Results are given for the orbital magnetic moments 〈Lδ〉 along high-symmetry magnetization directions δ and for the corresponding magnetic anisotropy energy ΔE. A compact five-fold symmetric Co7 cluster is considered as representative example. It is shown that with an appropriate choice of B the OP approximation yields a very good agreement with the rigorous orbital-dependent calculations. Moreover, one observes that the orbital-independent approach accounts qualitatively for the main general trends in 〈Lδ〉 and MAE. Advantages and limitations of the various approaches are discussed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computational Materials Science - Volume 35, Issue 3, March 2006, Pages 292–296
نویسندگان
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