Theoretical study of magnetic phase transitions of cubic SrMnO3 under physical and chemical pressures

A magnetic configuration phase transition from antiferromagnetic (AFM) to ferromagnetic (FM) ordering is observed in cubic SrMnO3 under negative pressure of −9 GPa by density functional calculations, while the ground state of G-type AFM ordering is maintained under the positive pressure. To realize the negative pressure, SrMnO3 with chemical pressure by Sr site doping of Ba and La ions is further investigated, respectively. It is found that the required negative pressure is reduced by ∼1 GPa for the cubic SrMnO3 favoring FM configuration when doped with Ba, though it keeps C- or G-AFM under positive pressures. In addition, the stability of G-AFM configuration is destroyed in cubic SrMnO3 when doped with La under various pressures.