Anomalous field-dependent specific heat in charge-ordered   Pr$_{1-x}$Ca$_x$MnO$_3$ and La$_{0.5}$Ca$_{0.5}$MnO$_3$
  We report low temperature specific heat measurements of Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ ($0.3\leq x \leq 0.5$) and La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ with and without applied magnetic field. An excess specific heat, $C^{\prime}(T)$, of non-magnetic origin associated with charge ordering is found for all the samples. A magnetic field sufficient to induce the transition from the charge-ordered state to the ferromagnetic metallic state does not completely remove the $C^{\prime}$ contribution. This suggests that the charge ordering is not completely destroyed by a "melting" magnetic field. In addition, the specific heat of the Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ compounds exhibit a large contribution linear in temperature ($\gamma T$) originating from magnetic and charge disorder. 
V. N. Smolyaninova, Amlan Biswas, X. Zhang, K. H. Kim, Bog-Gi Kim,   S-W. Cheong, and R. L. Greene