Specific heat of Nd1-xSrxMnO3 (x ∼ 0.5)

The specific heat of the single crystal of Nd1-xSrxMnO3 (x approximately equals 0.5) has been measured at 20 K < T < 280 K in H < 5T. Two specific heat anomalies are observed at TC approximately equals 255 K and TN approximately equals 157 K (x=0.5) and 164 K (x=0.5+d with d approximately equals 0.002). The former transition is attributed to the ferromagnetic order of Mn3+ and Mn4+ spins and the latter the charge and orbital orders at the ferromagnetic-antiferromagnetic (AF) transition. Double peak structure is seen at TN in the sample with x=0.5+d, but not for x=0.5. These two peaks are related to the phase segregation of the CE and A-type AF order phases in narrow x range of 0.5 < x < 0.52. 15 refs.