First principles theoretical study of complex magnetic order in transition-metal nanowires Article uri icon

abstract

  • The electronic and magnetic properties of one-dimensional (1D) transition-metal (TM) systems are investigated from a first principles theoretical perspective. The development of local magnetic moments and the stability of various collinear and non-collinear spin arrangements are determined in the framework of a generalized gradient approximation to density-functional theory (DFT). Two specific complementary problems are considered. The first one concerns the local moment formation in Cu wires doped with Co and Ni impurities. Recent results as a function of wire length, interatomic distances, impurity position within the wire, and total spin polarization $S_{z} $ are reviewed. It is shown that both Co and Ni impurities preserve their magnetic degree of freedom in monoatomic Cu wires by developing almost saturated local moments in all low-lying total spin configurations ($S_{z} \leq 5/2$). The impurity moments are largely dominated by the d-electron contributions. In the ground state they couple ferromagnetically with the moments induced at the Cu host atoms. The changes in the spin-density distribution and in the local densities of electronic states are quantified as a function of the position of the impurity position within the wire. In addition, recent results on the ground-state magnetic order in V nanowires are reviewed. The stability of ferromagnetic (FM), antiferromagnetic (AF), and spiral non-collinear (NC) orders is analyzed in terms of the frozen-magnon spectrum. A remarkable transition from FM to NC order is observed as a function of the nearest-neighbor (NN) distance a. The dependence of the single-particle electronic structure of the wire on the wave-vector of the spin-density wave (SDW) is demonstrated. Finally, the role of magnetic anisotropy on the stability of NC order is discussed in the framework of a simple classical spin model. © 2010 WILEY-VCH Verlag GmbH %26 Co. KGaA, Weinheim.

publication date

  • 2010-01-01