Control of localized states of itinerant electrons and their magnetic interactions

Abstract

Controlling the magnetic properties of nanosystems by an electric field offers a number of advantages for spintronics applications. Using the noncollinear Alexander-Anderson model, we have shown that the interaction of localized magnetic moments formed by itinerant electrons strongly depends on the position of the d-level relative to the Fermi level, which determines the number of localized electrons. Depending on this parameter, the ground state of the magnetic dimer can be ferromagnetic, antiferromagnetic, or noncollinear without the effects of spin-orbit interaction. The magnetic state can be controlled by shifting the d-level with an electric field, even without current flow. For a sufficiently large value of the hopping parameter between localized states there can be several self-consistent solutions with different values of magnetic moments. This opens new possibilities for manipulation of the magnetic structure of nanosystems. The results obtained lead to a new interpretation of the mechanisms of magnetization reversal, recording, and deleting of magnetic structures in tunneling spectroscopy experiments.

Figures (2)

• Figure 1: (Color online) Graphical solution of equation (\ref{['8']}) and the dependence of grand canonical potential of dimer $10\Delta \mathcal{G}/ \Gamma$ on 5$M$. All variants with different numbers of solutions are shown
• Figure 2: (Color online) Self-consistent magnetic moment per atom 5$M$ and grand canonical potential of dimer $10\Delta \mathcal{E} /\Gamma$ as functions of $d$-electron numbers 5$N$. Parameter values: $y=13$ (a,c) $v=2$, (b,d) $v=3$. Insets shows the region of non-collinear ground state