A novel stimulation: Tailoring conductivity transition in Gd_1-xCa_xBaCo₂O_5+δ (x=0-0.4) by microwave stimulation

Control of the insulator-metal transition (IMT) is a constant focus of intensive study, owing to its importance to the exploration of novel effects and in Information Technology. Complex oxides with competitive mechanisms are suitable objects of study in this regard, because of their susceptibility to external stimuli. The double-perovskite cobaltate Gd_1-xCa_xBaCo₂O_5+δ (GCBC) is one such oxide. In this paper, the combined effects of the GCBC structure and Ca²⁺ doping have been studied for 0≤x≤0.4, which offers the possibility of systemic modulation of the conductivity (σ) of the GCBC via microwave stimulation. The maximum value and rate of increase of σ increase with the microwave power, and it has been found that the conductivity of Gd_0.8Ca_0.2BaCo₂O_5+δ can increase from 158 to 1488 S/cm at a frequency of 2.45 GHz (1500 W) over 2 min. Thus, our experimental study confirms that microwaves are crucial for controlling the electrical properties of cobaltates.