Some Heusler compounds were predicted to have half-metallic electronic structures 1, which are important properties in spintronics. Then Co-substituted Mn3Ga Heusler films, which exhibit perpendicular magnetic anisotropy (PMA) and the magnetic transition from PMA to in-plane magnetic anisotropy (IMA), were considered to be potential spintronic materials 2,3. In this work, we have investigated electronic structures of Mn3-xCoxGa films by employing synchrotron radiation-excited soft X-ray absorption spectroscopy (XAS) and soft X-ray magnetic circular dichroism (XMCD). According to Co 2p XAS and XMCD, the substituted Co ions in Mn3-xCoxGa consist of ferromagnetic metallic Co clusters and divalent Co ions with disordered magnetic moments. Mn 2p XAS and XMCD show that Mn ions at both the octahedral and tetrahedral sites are nearly divalent, reflecting non Jahn-Teller ions, and that the magnetic moments of Mn ions are polarized along the ordered magnetic moments of the substituted Co ions. Angle-dependent Co 2p XMCD results agree with the weak PMA-IMA magnetic anisotropy transition with increasing Co content. This work reveals that the magnetic anisotropy transition in Mn3-xCoxGa is determined mainly by the ferromagnetic metallic Co clusters of the substituted Co ions.
The financial funding from the NRF of Korea (Project No. 2019R1A2C1004929) is gratefully acknowledged.
1 R. A. de Groot, et al., Phys. Rev. Lett. 50, 2024 (1983). 2 H. Kurt, et al., Phys. Rev. B 83, 020405(R) (2011). 3 Kyujoon Lee, et al., J. Alloys Compd. 858, 1582884 (2021).