Non-linear conduction in charge-ordered Pr${}_{0.63}$ Ca${}_{0.37}$ MnO${}_3$ : Effect of magnetic fields

Non-linear conduction in a single crystal of charge-ordered Pr${}_{0.63}$Ca${}_{0.37}$MnO${}_3$ has been investigated in an applied magnetic field. In zero field, the non-linear conduction, which starts at T$<$T${}_{CO}$ can give rise to a region of negative differential resistance (NDR) which shows up below the N'eel temperature. Application of a magnetic field inhibits the appearance of NDR and makes the non-linear conduction strongly hysteritic on cycling of the bias current. This is most severe in the temperature range where the charge ordered state melts in an applied magnetic field. Our experiment strongly suggests that application of a magnetic field in the CO regime causes a coexistance two phases.