Polaronic transport in the ferromagnetic phase of Gd1-xCaxBaCo2O5.53

TL;DR

This study investigates how calcium doping affects electrical transport in Gd1-xCaxBaCo2O5.53, revealing polaronic conduction mechanisms and stabilization of ferromagnetism at low temperatures.

Contribution

It demonstrates the role of Ca-induced holes in modifying resistivity and thermopower, highlighting polaronic transport in the ferromagnetic phase.

Findings

Calcium doping reduces resistivity significantly.

Polaronic transport explains temperature-dependent behavior.

Ferromagnetic phase is stabilized at low temperatures with doping.

Abstract

Temperature dependent electrical resistivity and thermopower measurements were carried out on Gd1-xCaxBaCo2O5.53 with x varying between 0 and 0.25. Ca subsitution leads to the incorporation of holes (Co4+) into the system that leads to a reduction in resistivity and a stabilisation of the ferromagnetic phase at low temperatures. The temperature dependence of resistivity and thermopower are markedly different in the Ca doped sample, with a dramatic reduction in the resistivity, as compared to that in the pristine sample. The variation in both the resistivity and thermopower with temperature is explained in terms of the transport of polarons in the ferromagnetic phase of Ca doped system.