Systematic theoretical study of the spin and orbital magnetic moments of 4d and 5d interfaces with Fe films

TL;DR

This paper presents a systematic ab initio study of spin and orbital magnetic moments at 4d and 5d transition metal interfaces with Fe, revealing layer-dependent behaviors and violations of Hund's rules linked to hybridization effects.

Contribution

It provides the first comprehensive layer-resolved analysis of magnetic moments across entire 4d and 5d series at Fe interfaces using relativistic density functional theory.

Findings

Fe spin moment is reduced at the interface.

W layers exhibit induced spin moments with alternating alignment.

Hund's third rule is violated in specific W layers.

Abstract

Results of ab initio calculations using the relativistic Local Spin Density theory are presented for the magnetic moments of periodic 5d and 4d transition metal interfaces with bcc Fe(001). In this systematic study we calculated the layer-resolved spin and orbital magnetic moments over the entire series. For the Fe/W(001) system, the Fe spin moment is reduced whilst its orbital moment is strongly enhanced. In the W layers a spin moment is induced, which is antiparallel to that of Fe in the first and fourth W layers but parallel to Fe in the second and third W layers. The W orbital moment does not follow the spin moment. It is aligned antiparallel to Fe in the first two W layers and changes sign in the third and fourth W layers. Therefore, Hund's third rule is violated in the first and third W layers, but not in the second and fourth W layers. The trend in the spin and orbital moments over the 4d and 5d series for multilayers is quite similar to previous impurity calculations. These observations strongly suggest that these effects can be seen as a consequence of the hybridization between 5d (4d) and Fe which is mostly due to band filling, and to a lesser extent geometrical effects of either single impurity or interface.