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Journal of Physical Studies 27(4), Article 4703 [5 pages] (2023)
DOI: https://doi.org/10.30970/jps.27.4703 MAGNETORESISTANCE AND HALL EFFECT CAUSED BY BERRY CURVATURE IN Sr2FeMoO6−δ DOUBLE PEROVSKITE
S. M. Konoplyuk
Institute of Magnetism of NASU and MESU,
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The paper focuses on transport properties of double perovskite Sr\textsubscript{2}FeMoO$_{6-δ}$, which were studied experimentally and using first principles calculations. The strontium ferromolybdate specimens were prepared using citrate-gel method followed by compacting and thermal treatment at different regimes. The Hall effect was calculated using Quantum Espresso and Wannier90 software packages.
The study confirmed high sensitivity of Sr\textsubscript{2}FeMoO\textsubscript{6} to the processing parameters such as pressure and temperature of powder compacting as well as the temperature and duration of the subsequent annealing in Ar/O\textsubscript{2} atmosphere. The optimal regime of compacting to avoid cracking involved pressing under 4 GPa at $T=800$ K. Further heat treatment of the compacted specimens in Ar/O\textsubscript{2} atmosphere has shown that three types of electric conductivity, namely metallic, semiconducting and mixed one can be realized in the Sr\textsubscript{2}FeMoO\textsubscript{6} specimens. The highest magnitude of magnetoresistance was found in the semiconducting specimen (about 44\
The Hall effect was computed by constructing the Hamiltonian in the maximally-localized Wannier functions basis. Calculations of the Berry curvature, which is the origin of the high intrinsic Hall effect showed that its highest magnitudes concentrate near avoided band crossings gapped out due to spin-orbit coupling. The Hall conductivity calculated by integrating the Berry curvature over all occupied bands was found to be $\sim 22$ S/cm.
Key words: Sr2FeMoO6, electric resistance, magnetoresistance, Hall effect, Berry curvature
