Magnetocaloric effect in (La_{0.7}Ca_{0.3})_{1 - x}Mn_{1 + x}O_3 manganites with x = 0, 0.1, 0.2 has been investigated. It is found a strong influence of nonstoichiometry caused by excessive manganese on the magnetic entropy change. The magnetocaloric effect was evaluated from the isothermal curves of spontaneous magnetization versus the applied magnetic field by using the well-known thermodynamical Maxwell relation. The maximum entropy value, | Δ S_{M}^{max} |, near the ferromagnetic-paramagnetic phase transition is shown to increase with the manganese content. The La_{0.56}Ca_{0.24}Mn_{1.2}O_3 manganite exhibits the largest | Δ S_{M}^{max} | value equal to 3.09 J kg^{-1} K^{-1} at 15 kOe near T_{C} = 267 K. The magnetocaloric effect values obtained allow to propose that the studied manganites are promising materials for future cooling application.
Measurements of magnetization and electric polarization performed for the TbMnO_3 film grown onto the single crystal [100] SrTiO_3 substrate using magnetron sputtering technique exhibit series of anomalies related to the magnetic and electric ordering of the Tb^{3+} and Mn^{3+} sublattices. The detailed temperature dependences of the electric polarization and dielectric constant of the TbMnO_3 film have shown that the ferroelectric phase appears below 30 K in magnetic field H > 1 T applied in-plane and out-of-plane of the film.
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