Prediction of room-temperature half-metallicity in layered halide double perovskites

Abstract

Half-metallic ferromagnets (HMFs) that possess intriguing physical properties with completely spin-polarized current are key candidates for high-efficiency spintronic devices. However, HMFs that could simultaneously have high Curie temperature (T c ), wide half-metallic gap (Δ HM ), and large bulk magnetocrystalline anisotropy energy (MAE) are very rare, which significantly restrict their room-temperature (RT) applications. In this article, through materials screening in layered halide double perovskites (LHDPs), we have theoretically identified that Cs 4 FePb 2 Cl 12 , which has good crystallographic, dynamic and thermal stabilities, possesses an intrinsic half-metallic ground-state with a high T c~4 50 K. Interestingly, the long-range ferromagnetic ordering in bulk Cs 4 FePb 2 Cl 12 is contributed by the strong super-superexchange interactions between the neighboring Fe d orbitals mediated by different anionic Cl p orbitals. The high T c of layered Cs 4 FePb 2 Cl 12 can be well maintained even in the monolayer limitation, i.e., T c~3 70 K for Cs 4 FePb 2 Cl 12 monolayer, which is critical for nanoscale device applications. Moreover, both bulk and monolayer Cs 4 FePb 2 Cl 12 can exhibit wide Δ HM~0 .55 eV and large MAE >320 μeV/Fe, comparable to that of the best HMFs reported in the literature. Our findings can significantly extend the potentials of LHDPs for high-temperature spintronic applications.npj Computational Materials (2019) 5:114 ; https://doi.

Strain-attenuated spin frustration in double perovskite Sr2FeOsO6

“…Therefore, the competition between magnetic interactions, the prime reason behind the low T N of the C-AFM phase without strain, can be controlled by heteroepitaxy. The complex interplay of tensile strain with the spin and orbital degrees of freedom establishes a FiM phase in Sr 2 FeOsO 6 and makes the compound a high-T C 3d-5d insulator with a large magnetic moment of 2μ B per formula unit (as Ca 2 FeOsO 6 ), which opens application potentials in spintronics [37][38][39] and magnetic storage devices [40][41][42]. The observation of an indirect-to-direct band gap transition under epitaxial strain and electron-hole separation between the Fe and Os sublattices is interesting for photovoltaics.…”

Phase driven magnetic and optoelectronic properties of La2CrNiO6: A DFT and Monte Carlo perspective

“…Based on these properties, the double perovskites have been applied in storage devices [15], magnetic cooling technologies [12], spintronics [16,17], opto-electronics [18], piezoelectrics [19] etc. For spintronics devices, a ferromagnetic insulator along with a non magnetic conductor restricts the electron transport through the non magnetic region.…”

p‐Type Transparent Quadruple Perovskite Halide Conductors: Fact or Fiction?

“…Recently, several quadruple perovskite halides with a general chemical formula of A 4 B II B III 2 X 12 (A = alkali metal; B II = Zn, Cd; B III = Sb, Bi; X = halogen) have been predicted to be the top p-type TCs [14] and have attracted a lot of attention. [15][16][17][18][19] Taking Cs 4 CdSb 2 Cl 12 as a representative example, defect calculations using the semilocal density functional theory (DFT) show that under Cl-rich conditions, Cs 4 CdSb 2 Cl 12 can exhibit excellent p-type conductivity with a high density of holes, because of the intrinsic shallow acceptor Cd Sb with an extremely low formation enthalpy. The predicted excellent p-type conductivity was explained by the delocalized Sb 5s orbitals and the antibonding character of the VBM.…”