Abstract :
Magnetotransport and magnetization measurements of the Cr-doped manganites Pr0.5Ca0.5Mn1−xCrxO3 (x=0.03,0.05) show several anomalous features: large magnetic field induced magnetic moments and negative magnetoresistance (MR) with hysteresis, strong deviation of susceptibility from Curie–Weiss law below 240 K in the paramagnetic insulating phase, large differences between zero field cooled and field cooled magnetization and hysteresis in MR and magnetization in the ferromagnetic metallic phase. On the basis of magnetic measurements we suggest that Cr3+ replaces Mn3+ with opposite spin. In agreement with our magnetic and transport measurements, we show that charge ordering coexists with ferromagnetism using electron microscopy. Electron microscopy work together with susceptibility data suggests that charge and orbital ordering occur at different temperatures.
