The metal-insulator transition in nanocrystalline Pr0.67Ca0.33MnO3: the correlation between supercooling and kinetic arrest

The transition and hysteresis widths of a disorder broadened first order magnetic transition vary in H-T space which influences the co-existing phase fraction at low temperature arising due to kinetic arrest of the first order transition. We explored the role of change in the relative width of the supercooling/ superheating band and kinetic arrest band for a ferromagnetic metallic to antiferromagnetic insulating transition. It is shown that for a correlated kinetic arrest and supercooling bands, the topology of the devitrification curves (or transformation across the (H-K, T-K) band during warming) changes with the change in the relative width of these two bands. In addition to this, for a broader kinetic arrest band, the transformation temperature across the superheating band under constant H now depends on the arrested phase fraction. These predictions have been tested on nanocrystalline Pr0.67Ca0.33MnO3, which is known to show a large variation in hysteresis width in H-T space. This is the first report where correlation between the kinetic arrest band and the supercooling band has been shown experimentally, in contrast to the universal observation of anticorrelation reported so far.