In this paper, the magnetocaloric effect of perovskite manganite La 0.67−x Eu x Sr 0.33 MnO 3 (x = 0.1 and x = 0.2) has been investigated. From the measurement of isothermal magnetization around the Curie temperature, we have calculated the maximum isothermal magnetic entropy change The maximum magnetic entropy change S max M is found to increase with increasing of Eu content from 4.10 J/kg K for x = 0.1 J/kg K and 4.33 J/kg K for x = 0.2 upon 5 T applied field change. It is suggested that La 0.67−x Eu x Sr 0.33 MnO 3 are suitable candidates as refrigerants near room temperature region.

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An investigation of the magnetic, magnetocaloric and electrical behavior of La(0.67)Ba(0.1)Ca(0.23)MnO3 is presented. The variation of magnetization (M) vs. temperature (T) under 1, 2, 3, 4 and 5 T magnetic fields reveals a ferromagnetic-paramagnetic transition. Magnetic entropy change, relative cooling power and specific heat for magnetic field variation were conducted using a phenomenological model. Moreover, the electrical resistivity is fitted with the phenomenological percolation model which is based on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. The equation of the form ΔS(P)(M)(T,H) = - α∫(H)(0)[∂(ln)(ρ)/∂(T)](H)(dH) relates the magnetic order to the transport behavior of our sample. The results show that the as obtained magnetic entropy change values are similar to those determined using data obtained from the investigation of the dependence of magnetization on the temperature and magnetic field.