Martensite-like transition and spin-glass behavior in nanocrystalline   Pr0.5Ca0.5MnO3
  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. 
S. Narayana Jammalamadaka, S. S. Rao, J. Vanacken, A. Stesmans, S. V.   Bhat and V. V. Moshchalkov
cond-mat.mtrl-sci cond-mat.str-el