Influence of charge and magnetic ordering on the insulator-metal transition in ${\mathrm{Pr}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Ca}}_{\mathit{x}}$${\mathrm{MnO}}_3$

A detailed study of the properties of ${\mathrm{Pr}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Ca}}_{\mathit{x}}$ ${\mathrm{MnO}}_3$ shows that for a range of compositions (0.3≤x<0.5) there is a first-order magnetic-field-induced insulator-metal transition. For the x=0.4 composition the magnetic and charge ordering (CO) effects are decoupled with antiferromagnetic (AFM) ordering, ${\mathit{T}}_{\mathit{N}}$=170 K, developing at considerably lower temperatures than the CO state, ${\mathit{T}}_{\mathrm{CO}}$=250 K. Below the CO temperature, metamagnetic transitions exist that transform the magnetic correlations from either paramagnetic or AFM to ferromagnetic. Metastable conducting states are formed below 25 K.