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MA: Fachverband Magnetismus

MA 39: Correlation Theory II

MA 39.2: Vortrag

Mittwoch, 18. März 2020, 15:15–15:30, HSZ 403

First principles calculations and Monte Carlo simulations of half-metallic CaCu₃Fe₃Re₂O₁₂ quadruple perovskite — •Duo Wang¹, Saurabh Ghosh², and Biplab Sanyal¹ — ¹Uppsala University, Uppsala, Sweden — ²SRM University, Chennai, India

Materials that have high spin-polarized conduction electrons at room temperature are very important for spintronic developments. Wentin Chen et al. have synthesized the quadruple perovskite CaCu₃Fe₃Re₂O₁₂, which shows half-metallic electronic structure, large magnetization and very high Curie temperature (up to 560K). We have performed density functional calculations on the ground state structure (CaCu²⁺(↑)₃Fe³⁺(↑)₂Re⁵⁺(↓)₂O₁₂), and calculated interatomic exchange interactions with the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method. We find that both J_Re−Cu and J_Re−Fe show strong antiferromagnetic coupling along with ferromagnetic coupling between Fe moments. This is consistent with ferrimagnetic nature of A₂FeReO₆ (A=Ca, Sr and Ba, respectively) double perovskite that the high Curie temperature indicate strong antiferromagnetic couplings. We also performed Monte Carlo simulations using the exchange parameters obtained from the FP-LMTO method. The magnetic transition temperature is found to be 295K. Besides that, the size of A-site cation will affect the crystal structure, magnetism, exchange interactions and also magnetic ordering temperature. Calculations to replace A-site atom (Ca) are ongoing.