  The Nd0.6Sr0.4MnO3 manganite system exhibits a phase transition from
paramagnetic insulating (PMI) to ferromagnetic metallic (FMM) state around its
Curie temperature TC = 270 K (bulk). The morphology-driven changes in the
kinetically arrested magnetic phases in NSMO thin films with granular and a
crossed-nano-rod-type morphology are studied. At low temperatures, the
manganite thin films possess a magnetic glassy state arising from the
coexistence of the high-temperature PMI phase and the low-temperature FMM
phase. The extent of kinetic arrest and its relaxation was studied using the
"cooling and heating in unequal field (CHUF)" protocol in magnetic and
magneto-transport investigations. The sample with rod morphology showed a large
extent of phase coexistence compared to the granular sample. Further, with a
field-cooling protocol, time-evolution studies were carried out to understand
the relaxation of arrested magnetic phases across these morphologically
distinct thin films. The results on the devitrification of the arrested
magnetic state are interpreted from the point of view of homogeneous and
heterogeneous nucleation of the FM phase in the PM matrix with respect to
temperature.
