Electronic and magnetic properties of the Co2MnAl/Au interface: Relevance of the Heusler alloy termination

• Ab initio electronic and magnetic properties of the interface Co2MnAl/Au.
• Two terminations were studied: Co2 and MnAl terminated.
• The termination of the Heusler alloy sensibly determines the interface properties.
• The Co2 terminated interface displays a higher spin polarization.

We present ab initio calculations of electronic and magnetic properties of the ferromagnetic metal/normal metal (F/N) interface of the Heusler alloy Co2MnAl and gold. Two structural models are implemented: one with the ferromagnet slab terminated in a pure cobalt plane (“Co2-t”), and the other with it terminated with a plane of MnAl (“MnAl-t”). The relaxed optimum distance between the slabs is determined for the two models before densities of states, magnetic moments, and the electric potential are resolved and analyzed layer by layer through the interface. Complementary, calculations for the free surfaces of gold and the Heusler alloy (for both models, Co2-t and MnAl-t) are performed for a better interpretation of the physics of the interface. We predict important differences between the two models, suggesting that both terminations are to be expected to display sensibly different spin injection performances.