Core polarity of screw dislocations in Fe–Co alloys

Abstract

In this paper, we show that the core of screw dislocations in Fe–Co alloys changes from a non-degenerate to a degenerate structure in analogy to W–Re alloys. This result is consistent with the similar d-band filling of non-magnetic W–Re and ferromagnetic Fe–Co. The transition in core polarity is shown to occur around 50 at% Co. Furthermore, we find that the magnetic moment in the dislocation core increases for Fe but decreases for FeCo.

Keywords:

• dislocations
• core polarity
• iron cobalt alloys

Acknowledgments

We thank D Terentyev for stimulating discussions and G Kresse for providing VCA POTCAR files. Financial support from the Austrian COMET Research Funding Programme and from the HPC-FF supercomputing facility is gratefully acknowledged.