REENTRANT TRANSITION OF THE CHARGE-ORDERED STATE IN PEROVSKITE MANGANITES

The stability of the charge-ordered state against variations of temper ature(T) and external magnetic field (H) has been investigated for Pr- 0.65/Ca1-ySry)(0.35)MnO3 crystals with controlled one-electron bandwid th. For y = 0.3. the charge- and orbital-ordering appears below 200 K as in the y < 0.3 crystals, but collapses into the metallic state belo w 100 K. Under a magnetic field, such a reentrant feature is observed in a wider region of y (< 0.3). A variation of the H-T phase diagrun f or the charge-ordered state with the one-electron bandwidth is present ed in view of the origin of the colossal magnetoresistance.