Effects of cationic growth conditions of molecular beam epitaxy on ferromagnetic properties of Mn-doped ZnSnAs₂ thin films

The effects of cationic growth parameters of molecular beam epitaxy on the crystalline and magnetic properties of Mn-doped ZnSnAs₂, (Zn,Sn,Mn)As₂, thin films were investigated in order to control ferromagnetism at room temperature. The combination of cationic beam equivalent pressures of Zn, Sn, and Mn atoms was varied at an optimal substrate temperature of 320°C. Clear hysteresis loops were observed for the samples at 300 K, indicating ferromagnetism at room temperature. We found that the change in Zn flux does not significantly affect the composition of (Zn,Sn,Mn)As₂ thin films and ferromagnetic properties and that ferromagnetic properties definitely depend on the amounts of Mn and Sn fluxes. X-ray photoelectron spectroscopy analysis revealed that the sum of the amounts of Mn²⁺ and Mn⁴⁺, which may contribute to the ferromagnetism in (Zn,Sn,Mn)As₂ thin films, was approximately 60–70% of the total Mn amount with respect to ferromagnetic (Zn,Sn,Mn)As₂ samples. This result indicates that the ferromagnetic properties could be controlled in multilayered (Zn,Sn,Mn)As₂ by changing the combination of Zn, Sn, and Mn fluxes. (author)