Ab initio density functional calculations of ferromagnetism in low-dimensional nanostructures: From nanowires to nanorods
Authors | |
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Year of publication | 2009 |
Type | Article in Periodical |
Magazine / Source | Physical Review B |
MU Faculty or unit | |
Citation | |
Field | Solid matter physics and magnetism |
Keywords | magnetism of nanostructures; nanowires; iron; nickel |
Description | We present ab initio spin-density functional calculations of the electronic and magnetic properties of Fe and Ni nanostructures with a geometry varying between a straight linear wire and a three-dimensional nanorod. With decreasing tension along the axis of the nanostructure we find a series of transitions first from dimerized to periodic and zigzag wires, then to a planar triangular stripe, and further to a nanorod consisting of a periodic stacking of triangular antiprims. In all nanostructures atoms are in a high-moment state, with magnetic moments of about 3.1muB for Fe and about 1muB for Ni. A transition to a low-spin or nonmagnetic state is initiated at a fixed critical value of the interatomic distance, independent of dimension and coordination number. The analysis of the electronic structure shows that already for the one-dimensional nanostructures the ratio between exchange splitting and magnetic moment is close to the universal value I=Delta/M=1 eV/muB established for bulk itinerant magnets. |
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