Sanyal, P., Halder, A., Si, L., Wallerberger, M., Held, K., & Saha-Dasgupta, T. (2016). Magnetism in Sr₂ CrMoO₆: A combined ab initio and model study. Physical Review B, 94(3), Article 035132. https://doi.org/10.1103/physrevb.94.035132
Using a combination of first-principles density functional theory (DFT) calculations and exact diagonalization studies of a first-principles derived model, we carry out a microscopic analysis of the magnetic properties of the half-metallic double perovskite compound, Sr₂CrMoO₆, a sister compound of the much discussed material Sr₂FeMoO₆. The electronic structure of Sr₂CrMoO₆, though appears similar to Sr₂FeMoO6 at first glance, shows non trivial differences with that of Sr₂FeMoO₆ on closer examination. In this context, our study highlights the importance of charge transfer energy between the two transition metal sites. The change in charge transfer energy due to shift of Cr d states in Sr₂CrMoO₆ compared to Fe d in Sr₂FeMoO₆ suppresses the hybridization between Cr t₂g and Mo t₂g. This strongly weakens the hybridization-driven mechanism of magnetism discussed for Sr₂FeMoO₆. Our study reveals that, nonetheless, the magnetic transition temperature of Sr₂CrMoO₆ remains high since additional superexchange contribution to magnetism arises with a finite intrinsic moment developed at the Mo site. We further discuss the situation in comparison to another related double perovskite compound, Sr₂CrWO₆. We also examine the effect of correlation beyond DFT, using dynamical mean field theory (DMFT).
