Dependence of the heat capacity of La$_{1-x}$Ag$_x$MnO$_3$ manganites on the Ag content

The heat capacity of La_1−x Ag _x MnO₃ manganites with x = 0.1, 0.15, and 0.2 is measured in the temperature range 77–350 K. An analogy between the effect of doping and the effect of a magnetic field on the temperature dependence of heat capacity of the La_1−x Ag _x MnO₃ system is revealed. As lanthanum is replaced by silver, the volume fraction of the ferromagnetic phase increases, while, in the paramagnetic state, the Jahn-Teller distortions are eliminated. The results of the aforementioned measurements suggest that the phase transition near the Curie point is caused by the competition between the Coulomb and exchange electrostatic interactions. The comparison of the concentration dependences of T _C for La_1−x Sr _x MnO₃ and La_1−x Ag _x MnO₃ points to good potentialities of the latter system from the viewpoint of applications.