Impact of Antisite Disorder on the Resistivity of Strontium Ferromolybdate Ceramics

In this work, we consider the influence of antisite disorder, e.g., Fe ions on Mo sites, FeMo, and vice versa, MoFe, on the resistivity of strontium ferromolybdate ceramics fabricated by the solid-state reaction method. Strontium ferromolybdate ceramics fabricated via solid-state reactions exhibit a low-temperature minimum resistivity owing to the interplay between the bulk metallic resistivity of the grains, which increases with temperature and becomes dominant at higher temperatures, and an intergrain tunneling mechanism of charge carrier conduction, which leads to a decrease in conductivity with decreasing temperature in the low-temperature region. The parameters of the bulk metallic resistivity and fluctuation-induced intergrain tunneling were determined by fitting the experimental data to these resistivity models. The impact of antisite disorder on the resistivity parameters was considered. It turns out that antisite disorder affects the effective barrier height of intergrain tunneling and the effective values of the barrier width and the barrier area. Disorder increases the effective barrier height for intergrain tunneling, increases its barrier width, and decreases the effective barrier area of nanosized barriers. The results are discussed using experimental data available in the literature.