  We report on isothermal pulsed (20 ms) field magnetization, temperature
dependent AC - susceptibility, and the static low magnetic field measurements
carried out on 10 nm sized Pr0.5Ca0.5MnO3 nanoparticles (PCMO10). The
saturation field for the magnetization of PCMO10 (~ 250 kOe) is found to be
reduced in comparison with that of bulk PCMO (~300 kOe). With increasing
temperature, the critical magnetic field required to 'melt' the residual
charge-ordered phase decays exponentially while the field transition range
broadens, which is indicative of a Martensite-like transition. The AC -
susceptibility data indicate the presence of a frequency-dependent freezing
temperature, satisfying the conventional Vogel-Fulcher and power laws, pointing
to the existence of a spin-glass-like disordered magnetic phase. The present
results lead to a better understanding of manganite physics and might prove
helpful for practical applications.
