Electric-field-driven resistive transition in multiferroic SrCo2Fe16O27/Sr3Co2Fe24O41 composite

Abstract

We report on the observation of electric-field-driven resistive transition [abrupt rise in resistivity ([Formula: see text])] at a characteristic threshold field [Formula: see text] in an off-stoichiometric composite of W- and Z-type hexaferrite ([Formula: see text]80%)[Formula: see text]/([Formula: see text]20%)[Formula: see text]. The dielectric constant [Formula: see text] and the relaxation time constant [Formula: see text] also exhibit anomalous jump at [Formula: see text]. The [Formula: see text], the extent of jump in resistivity ([Formula: see text]), and the hysteresis associated with the jump [[Formula: see text]] are found to decrease systematically with the increase in temperature ([Formula: see text]) across a range of 10–200 K. They also depend on the extent of nonstoichiometry. In addition, several temperature-driven phase transitions have been noticed both in the low and high resistive states. The entire set of observations has been discussed within the framework of structural evolution of the point defect (cation vacancies or oxygen excess) network and its influence on electronic conduction. The magnetocapacitive effect, measured under [Formula: see text]20 kOe field, turns out to be substantial ([Formula: see text]4%–12%) and exhibits clear anomaly at [Formula: see text]. This comprehensive map of esoteric [Formula: see text] and [Formula: see text] patterns provides insights on defect-driven effects in a multiferroic composite. These effects could be useful for tuning both the resistive transition and the multiferroicity.