Heat capacity of multiferroics Bi$_{1-x}$Pr$_{x}$FeO$_{3}$

The heat capacity of multiferroics Bi$_{1-x}$Pr$_{x}$FeO$_{3}$ (0 $\le x\le$ 0.20) has been studied in the temperature range 130–800 K. An insignificant substitution of praseodymium for bismuth is found to lead to a noticeable shift of the antiferromagnetic phase transition temperature and to an increase in the heat capacity in the temperature range 240–780 K. The temperature dependence of the excess heat capacity is shown to be due to the Schottky effect for three-level states. The temperature dependences of the heat capacity of the compositions with $x$ = 0.10 and $x$ = 0.15 and 0.20 exhibit additional anomalies characteristic of the phase transitions at $T\approx$ 755 K and $\approx$ 710 K, respectively. The results are discussed in combination with the data of structural studies.