Exploring the Magnetism and Magnetocaloric Effect of W‐Doped VO2 Based on J1–J2 Ising Model

Abstract

W‐doped VO2 exhibits a significant reduction in the metal–insulator transition temperature. In this study, the authors aim to investigate the magnetic influences of different proportions of W doping in VO2 with a rutile structure, using the J1–J2 model. The J1 and J2 values are calculated as 1.21 and −0.024 eV, respectively, using the generalized gradient approximation (GGA)+U method. Additionally, the J1–J2 model without W doping (x = 0) is simulated using the Ising model, and the obtained phase transition temperature of approximately 361 K closely matches the temperature calculated by Zheng et al. based on the spin dimer model. Furthermore, employing this model, the magnetization curves and magnetic entropy change (ΔS) are simulated for different W doping levels (x = 0–0.2). Through comprehensive analysis, it is found that the system exhibits the most promising research potential at a doping level of x = 0.12. These findings deepen the understanding of the mechanisms underlying the magnetic effects of W‐doped VO2 and provide a theoretical model guidance for future development of vanadium oxide materials.