First-principles simulation of electric and magnetic properties of Sr2FeMoO6 and analysis of its thermoelectric properties

Abstract

SUMMARYUsing a first-principles approach, we investigate the electronic and magnetic properties of the double-perovskite half-metal Sr 2 FeMoO 6 . We discuss our experimental studies of the thermoelectric properties of this compound, and our computer-simulation data, which indicate that its magnetic structure is a strong function of the location of the oxygen sites within the crystal lattice. We find experimentally that the Seebeck coefficient is about 10 to 15 µV/K, while the electrical resistivity is of order 10 -4Ω⋅m. We also argue that by skillfully controlling these parameters experimentally, it may be possible to realize a latent high thermoelectric conversion efficiency in this material, although verification of this requires further analysis and experimental study of properties such as the amount of magnetic disorder. In conclusion, we argue that while there has been almost no applications research done on this class of halfmetals, our simulation and experimental work indicate that high thermoelectric performance could be theoretically possible, which provides an indicator of what direction research on future applications of this material should follow.

Structure and thermoelectric properties of double-perovskite oxides: Sr₂₋<i>_x</i>K<i>_x</i>FeMoO₆

“…They possess an unusual electronic structure in which electrons with one spin have semiconducting properties and electrons with the opposite spin have metallic properties. 19), 20) An additional peculiarity of their electronic structure is that all the conduction electrons are completely spin-polarized in the vicinity of the Fermi level.…”

Thermoelectric properties of double-perovskite oxide Sr_2-<i>x</i><i>M</i>_<i>x</i>FeMoO₆ (<i>M</i> = Ba, La)

“…Moreover, some double-perovskite oxides are called half-metals, a new class of materials, neither metals nor insulators nor semiconductors, possessing an unusual electronic structure in which the electrons with one spin have semiconductor properties and the electrons with the other spin have metallic properties. 20), 21) An additional peculiarity of their electronic systems is that all the conduction electrons are completely spin-polarized in the vicinity of the Fermi level. 22),23) Half-metals also exhibit peculiar magnetic properties, a giant magnetoresistance effect in which a magnetic field induces a large change in the electrical resistivity, and tunneling magnetresistance (TMR) mediated by coupling JCS-Japan between spins and the conduction electrons.…”