Hall coefficient and oxygen stoichiometry inYBa2Cu3O7−δceramics at elevated temperatures

Abstract

The Hall coefficient and resistivity of polycrystalline ceramic samples of $\mathrm{Y}{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ were measured at elevated temperatures and at various ambient ${\mathrm{O}}_2$ partial pressures and correlated with separate thermogravimetric measurements of $\delta$. In the region where the oxygen stoichiometry reaches equilibrium with the external ${\mathrm{O}}_2$, it is shown by isothermal plots that the Hall number density decays exponentially with increasing $\delta$ and the effective Hall mobility is weakly dependent on $\delta$. Although transport coefficients are temperature dependent, this result lends support to the picture that oxygen doping in the cuprate acts mainly to modulate the density of hole carriers.