Antiferromagnetic coupling in perpendicularly magnetized cubic and tetragonal Heusler bilayers

• We studied on structural and magnetic properties of Co2MnSi/MnGa bilayers.
• Epitaxial bilayer films have been successfully grown even for an unannealed sample.
• We have confirmed epitaxy of the L21 ordered Co2MnSi on D022-MnGa film.
• Strong exchange coupling about −3.2 erg/cm2 was found for a bilayer annealed at 400 °C.

Epitaxial bilayer of tetragonal Heusler-like D022-MnGa and cubic Heusler L21-Co2MnSi have been successfully grown even for an unannealed sample. The interfacial exchange coupling (Jex) for samples annealed at different temperatures was evaluated from the magnetic hysteresis loop. Antiferromagnetic Jex was observed in the interfaces of cubic Heusler Co2MnSi and tetragonal D022-MnGa layers. The evaluated Jex is −3.2 erg/cm2 for a bilayer film annealed at 400 °C, being comparable to that for the FeCo/MnGa interface.