The electronic structure and atomic magnetic moments of clusters NdFe_6, NdFe_6N_3 and Fe_8 with a dumbbell atom-pair in rare earth-transition element compounds Nd_2Fe_(17)N_ x ( x =0, 3) were studied by spin-polariz...The electronic structure and atomic magnetic moments of clusters NdFe_6, NdFe_6N_3 and Fe_8 with a dumbbell atom-pair in rare earth-transition element compounds Nd_2Fe_(17)N_ x ( x =0, 3) were studied by spin-polarized MS-Xα method. The results are as follows: There are three negative exchange couplings between Fe(c) and Fe(f) atoms in Nd_2Fe_(17), which occur at their odd parity orbitals. Compared to the results of α-Fe calculated by the MS-Xα method, the low Curie temperature of compounds RE_2Fe_(17) can be explained satisfactorily. (2) There is only one weaker negative exchange coupling orbital leaving in between Fe(c) and Fe(f) sites in Nd_2Fe_(17)N_3. These results may be helpful for understanding the effect of interstitial atom M (M=N, H or C) in Fe_2Fe_(17)M_ x on Curie temperature. The other key factors affecting the Fe-Fe exchange coupling in Fe_2Fe_(17) compounds were also discussed.展开更多
文摘The electronic structure and atomic magnetic moments of clusters NdFe_6, NdFe_6N_3 and Fe_8 with a dumbbell atom-pair in rare earth-transition element compounds Nd_2Fe_(17)N_ x ( x =0, 3) were studied by spin-polarized MS-Xα method. The results are as follows: There are three negative exchange couplings between Fe(c) and Fe(f) atoms in Nd_2Fe_(17), which occur at their odd parity orbitals. Compared to the results of α-Fe calculated by the MS-Xα method, the low Curie temperature of compounds RE_2Fe_(17) can be explained satisfactorily. (2) There is only one weaker negative exchange coupling orbital leaving in between Fe(c) and Fe(f) sites in Nd_2Fe_(17)N_3. These results may be helpful for understanding the effect of interstitial atom M (M=N, H or C) in Fe_2Fe_(17)M_ x on Curie temperature. The other key factors affecting the Fe-Fe exchange coupling in Fe_2Fe_(17) compounds were also discussed.
