Magnetic properties and magnetocaloric effect of Sr-doped Pr0.7Ca0.3MnO3 compounds

In this work, we pointed out that Sr substitution for Ca leads to modify the magnetic and magnetocaloric properties of Pr0.7Ca0.3-xSrxMnO3 compounds. Analyzing temperature dependence of magnetization, M(T), proves that the Curie temperature (T-C) increased with increasing Sr content (x); T-C value is found to be 130-260 K for x = 0.0-0.3, respectively. Using the phenomenological model and M(T,H) data measured at several applied magnetic field, the magnetocaloric effect of Pr0.7Ca0.3-xSrxMnO3 compounds has been investigated through their temperature and magnetic field dependences of magnetic entropy change Delta S-m(T,H) and the change of the specific heat change Delta C-P(T,H). Under an applied magnetic field change of 10 kOe, the maximum value of -Delta S-m is found to be about 3 J/Kg.K, and the maximum and minimum values of Delta C-P(T) calculated to be about +/- 60 J/kg.K for x = 0.3 sample. Additionally, the critical behaviors of Pro Pr0.7Ca0.3-xSrxMnO3 compounds around their T-C have been also analyzed. Results suggested a coexistence of the ferromagnetic short- and long-range interactions in samples. Moreover, Sr-doping favors establishing the short-range interactions.