Interplay between Chemical and Magnetic Order in FeRh Clustersстатья из журнала
Аннотация: The structure, chemical order, and magnetic behavior in small FeRh clusters having N ≤ 19 atoms have been investigated theoretically. For N ≤ 6 atoms, a thorough global geometry optimization is performed by considering all possible cluster topologies, while for 7 ≤ N ≤ 19 only a few representative structures are considered. In all cases, the starting structures are fully relaxed in the entire range of concentrations and spin polarizations. The calculations are based on a generalized-gradient approximation to density-functional theory. The results are analyzed systematically as a function of size and composition. The optimized cluster structures are compact with a clear tendency to maximize the number of nearest-neighbor FeRh pairs. For very small sizes, the low-lying isomers present usually a topology different from that of the optimal structure, while for larger clusters the lowest-energy isomerizations imply mainly changes in the chemical order. The most stable structures are in general ferromagnetic. Antiparallel spin arrangements are found in some low-lying isomers. An important enhancement of the local Fe moments is observed as result of Rh doping. This is shown to be a consequence of an increase in the number of Fe d holes due to Fe–Rh charge transfer. The local moments at the Rh atoms, which are significant already in small pure Rh clusters, are not strongly enhanced by Fe doping. Nevertheless, the overall stability of magnetism, as measured by the energy gained upon spin polarization, increases with Fe content. The influence of spin–orbit interactions on the cluster stability and spin order is discussed.
Год издания: 2012
Авторы: Junais Habeeb Mokkath, G. M. Pastor
Издательство: American Chemical Society
Источник: The Journal of Physical Chemistry C
Ключевые слова: Magnetic and transport properties of perovskites and related materials, Magnetic properties of thin films, Advanced Condensed Matter Physics
Открытый доступ: closed
Том: 116
Выпуск: 32
Страницы: 17228–17238