First-Principles study of the structural, electronic, magnetic, and ferroelectric properties of hypothetical La0.75Bi0.25Cr1-xFexO3 solid solutions

[Display omitted] •Hypothetical La0.75Bi0.25Cr1-xFexO3 solid solution.•Bandgap of 2.18 eV for La0.75Bi0.25Cr0.5Fe0.5O3, and 2.11 eV for La0.75Bi0.25Cr0.25Fe0.75O3.•The La0.75Bi0.25Cr0.5Fe0.5O3 solid solution shows a ferromagnetic order with magnetization total of 15.98 μB/cell.•The La0.75Bi0.25Cr0.25Fe0.75O3 solid solution shows a ferrimagnetic order with magnetization total of 2.14 μB/cell.•Polarization of 11.43 μC/cm2 for La0.75Bi0.25Cr0.5Fe0.5O3 and 9.02 μC/cm2 for La0.75Bi0.25Cr0.25Fe0.75O3. Calculations based on the density functional theory were conducted to identify the presence of multiferroic properties in a hypothetical La0.75Bi0.25Cr1-xFexO3 solid solution with x = 0.5 and 0.75. This substance was based on a combination of the ferroelectric state in La0.75Bi0.25CrO3. The magnetic properties were induced by substituting Cr3+ with Fe3+ occupying the B site. The ferromagnetic order was more stable in the La0.75Bi0.25Cr0.5Fe0.5O3 solid solution with a total magnetization MT = 15.89 μB/cell in the ground state. Conversely, a ferrimagnetic order prevailed in the La0.75Bi0.25Cr0.25Fe0.75O3 solid solution. The formation energy demonstrated that the substances were energetically stable with a high potential for synthesis. The band gap values of the substances were in a range of 2.11–3.24 eV, which was indicative of their potential application as magnetic semiconductors. The La0.75Bi0.25Cr0.5Fe0.5O3 and La0.75Bi0.25Cr0.25Fe0.75O3 solid solutions with orthorhombic structures exhibited ferroelectric properties with spontaneous polarization values of 11.43 μC/cm2 (along the [101] direction) and 9.02 μC/cm2 (along the [1¯ 01] direction), respectively. The coexistence of the ferroelectric and ferromagnetic (ferrimagnetic) orders in the La0.75Bi0.25Cr0.5Fe0.5O3 (La0.75Bi0.25Cr0.25Fe0.75O3) solid solution promoted the potential for coupling between the magnetization and polarization, giving these materials significant potential for use in magnetoelectric devices.