Insight into electronic and magnetic properties of Ba2NiOsO6 double perovskite: A Monte Carlo study and a comparative investigation between TB-mBJ and GGA plus U

The structural, electronic, and magnetic properties of the Ba2NiOsO6 double perovskite were comprehensively studied using density functional theory (DFT) and Monte Carlo simulations. Based on DFT calculations, we found that the double perovskite is stable in the ferromagnetic phase. The compound exhibited thermodynamic stability, confirmed by its negative formation energy and phonon spectrum. The electronic and magnetic properties were analyzed using various approximations, including the Generalized Gradient Approximation (GGA), modified Becke-Johnson approximation (mBJ), and Hubbard correction (GGA+U). The electronic profile indicated a metallic nature with GGA and a half-metallic nature with GGA+U and mBJ. The total magnetic moment was approximately 4 mu B across all approximations. The Monte Carlo simulations revealed intriguing phenomena, such as a tri-critical point, second-order and first-order phase transitions, a reentrant phenomenon, and both simple and double hysteresis loops.