Effect of pressure on the geometric, electronic structure, elastic, and optical properties of the normal spinel MgFe<sub>2</sub>O<sub>4</sub>: a first-principles study
Hamada H. Kora, Mohamed Taha, Abdalla Abdelwahab, Ahmed A. Farghali, S.I. El‐Dek
Abstract
Abstract First-principles computation was used to study the effect of pressure on the elastic properties, magnetic properties, optical properties, and electronic structure of the normal spinel magnesium ferrite (MgFe 2 O 4 ) at different pressures (0, 10, 20, 50, 70, and 100 GPa). The normal spinel MgFe 2 O 4 has a direct bandgap of 1.62 eV which significantly decreased to 0.42 eV with increasing the pressure to 100 GPa. The values of the elastic constants were coherent with the mechanical stability norms for cubic crystals, which revealed that MgFe 2 O 4 was mechanically stable. The values of Pugh’s ratio indicate that MgFe 2 O 4 is ductile at all pressure values except at 100 Gpa MgFe 2 O 4 shows brittle behavior. The computed values of the Zener anisotropy factor at different pressures were not equal to 1.0, which indicates that MgFe 2 O 4 is elastically anisotropic. The optical properties (refractive index, reflectivity, dielectric function, optical conductivity, and loss function) for the normal spinel MgFe 2 O 4 , as well as its magnetic moment, were calculated and discussed at different pressures.