Effect of Coulomb blockade on the low-temperature resistivity minimum of nanomanganite La2/3Ca1/3MnO3

The unusual low-temperature resistivity minimum of nanomanganite La2/3Ca1/3MnO3 (LCMO) is presented in this paper. It is found that the resistivity upturn becomes steeper when the gain size gets smaller. As grain size is closely related to Coulomb blockade (CB), corresponding changes are made to a phenomenological model which failed to fit the low-temperature behavior before. This modified model is in excellent accord with the experimental data once the effect of CB is taken into consideration. This result strongly supports the inclusion of CB as one of the crucial origins of this unusual minimum behavior.