Effects of cation disorder and size on metamagnetism in A-site substituted Pr0.5Ca0.5MnO3 system

The effects of A-site cation disorder and size on metamagnetism of ABO3 type charge and orbital ordered Pr0.5Ca0.5MnO3 system have been studied by substituting Ba+2 for Ca+2 or La+3 for Pr+3. Substitution of 5% Ba+2 or 5% La+3 drastically reduces the critical magnetic field (Hc) for metamagnetism and induces successive steplike metamagnetic transitions at low temperatures. Interestingly, with further increase in substitution, Hc rises. We find that there is a sharp decrease in electrical resistivity corresponding to the metamagnetic transitions, which is indicative of strongly correlated magnetic and electronic transitions in these manganites.