Tunneling conduction mechanisms in strontium ferromolybdate ceramics with strontium molybdate dielectric intergrain barriers

This work is a contribution to the understanding of the electrical resistivity in strontium ferromolybdate (Sr2FeMoO6-delta, SFMO) ceramics. It demonstrates that an appropriate thermal treatment leads to the formation of dielectric SrMoO4 shells at the surface of SFMO nanograins. In samples without SrMoO4 shells, the sign of the temperature coefficient of resistance changes with increasing temperature from negative at very low temperatures to positive at higher temperatures. Samples exhibiting a negative temperature coefficient contain SrMoO4 shells and demonstrate a behavior of the resistivity that can be described in terms of the fluctuation-induced tunneling model, and near room temperature the conductivity mechanism converts to a variable-range hopping one. The results of this work serve as a starting point for the understanding of the low-field magnetoresistance which is very promising for spintronic device application. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the electrical resistivity in strontium ferromolybdate ceramics and found that the formation of dielectric SrMoO4 shells at the surface of nanograins affects the sign of the temperature coefficient of resistance. The results provide insights into the low-field magnetoresistance and its potential applications in spintronic devices.