Fully relaxed magnetic structure of transition metal nanowires: First-principles calculations

Abstract

We present fully relaxed magnetic structures of domain walls in magnetic transition metal nanocontacts ͑Ni, Co, and Fe͒ calculated from first principles. The domain wall is pinned in a monatomic nanowire, which is suspended between two semi-infinite leads. We show that the magnetization profile of the domain wall differs from the known Bloch and Néel walls. In particular, a "separation angle" between the directions of the moments of the outermost atoms and a clustering of the inner moments is observed. In addition, we calculate the conductance using the Landauer approach generalized to noncollinear magnetic structures. It is shown that the noncollinear magnetic order has considerable effect on the transport properties of the nanowires.

Observation of a bias-dependent constrained magnetic wall in a Ni point contact

“…Remarkably, the magnetic moment of Ni2 is found to be 0.059 B , meaning that our calculation reproduces a softening of a magnetic moment as have similarly reported in theoretical prominent works. 22,23 The softening is a significant proof of the existence of a constrained DW, and thus, the transition MPC region comprised of these three Ni atoms represents a constrained DW very well. Our calculations further demonstrate that the softening of the magnetic moment is valid even for the nonequilibrium state.…”

Spin and charge transport through non-collinear magnetic nanowires

“…Most recently, it was found that similar effects can be also seen in atomically thin chains of magnetic atoms ( [12] and references therein). Due to magnetic exchange interaction, the magnetic moments of the atoms are strongly correlated forming a noncollinear magnetic structure similar to the DW, and the electrons are transmitted through the atomic chain strongly affected by magnetic non-collinearity.…”

“…Namely, we consider the case when the DW width L is of the order of the electron wavelength l $ L, or it can be a thin DW with L 5l. In the bulk metallic ferromagnets, the inequality is usually just opposite, but in the case of magnetic nanowires or in nanoconstrictions the DW width can be dramatically decreased to the order of atomic length [12]. One can also reach the large l in magnetic semiconductors in the regime of weak or moderate…”

Electronic picture of spin-polarized tunneling with a Cr tip

“…Our self-consistent calculations were done by means of the KKR Green's function method within the local spin-density approximation of the density functional theory [10] with an extension to non-collinear magnetism [11][12][13][14]. Ballistic conductance was calculated in the framework of the Landauer-Büttiker approach using KKR Green's functions including non-collinear magnetic order [12].…”