Co1-xFexS2: a tunable source of highly spin-polarized electrons

Phys Rev Lett. 2005 Feb 11;94(5):056602. doi: 10.1103/PhysRevLett.94.056602. Epub 2005 Feb 11.


In the emerging field of spin-electronics ideal ferromagnetic electron sources would not only possess a high degree of spin polarization, but would also offer control over the magnitude of this polarization. We demonstrate here that a simple scheme can be utilized to control both the magnitude and the sign of the spin polarization of ferromagnetic CoS2, which we probe with a variety of techniques. The position of the Fermi level is fine-tuned by solid solution alloying with the isostructural diamagnetic semiconductor FeS2, leading to tunable spin polarization of up to 85%.