Anomalous temperature dependence of magnetic properties in Mn-doped ZnSnAs2 epitaxial thin films

We have observed anomalous temperature dependence of magnetization of ZnSnAs
₂
:Mn epitaxial thin films grown on InP(001) substrates compared with the values estimated by the mean-field theory using S = 5/2, as a function of temperature: The ZnSnAs
₂
:Mn epitaxial thin films exhibits slightly increasing magnetization with rising temperature. From the first-principles calculation, when Mn substitutes for neighboring Zn sites in ZnSnAs
₂
, MnZ
_n
-MnZ
_n
pairs result, which prefer antiferromagnetic (AFM) ordering. On the other hand, MnZ
_n
-MnS
_n
and MnS
_n
-MnS
_n
pairs can introduce both holes and spins, leading to ferromagnetic (FM) ordering. Thus, assuming that the magnetic property of ferromagnetic phase follows the mean-field theory, it can be explained by coexistence of FM and AFM phases.