Pressure-temperature phase diagram of charge order in Nd(0.5)Sr(0.5)MnO(3)

We observe how the charge-ordering (CO) temperature T(CO) of Nd(1/2)Sr(1/2)MnO(3) decreases with the external pressure p from 160K at p = 0 down to 30K at p similar or equal to 4.5 GPa, by measuring the values p, T where the far-infrared spectral weight of the metallic phase is fully recovered. We thus determine the (p, T) phase diagram of CO in that manganite. We also find that the parameter d(lnT(CO))/dp which describes this metallization from the CO phase is equal and opposite to the quantity d(lnT(c))/dp which governs the metallization of the paramagnetic state at comparable Curie temperatures T(c), in similar manganites at half-doping. Copyright (C) EPLA, 2010