Effect of iron substitution on the structural, magnetic and magnetocaloric properties of Pr_0.6Ca_0.1Sr_0.3Mn_1−xFe_xO₃ (0 ⩽ x ⩽ 0.075) manganites

Highlights: • The Pr_0.6Ca_0.1Sr_0.3Mn_1−xFe_xO₃ (x = 0, 0.025, 0.05, 0.075) compounds were synthesized using the Pechini sol–gel method. • Large magnetocaloric effect is reported based on second order phase transition. • Noticeable |ΔS_M| at low field makes the system useful for magnetic refrigeration. - Abstract: The effects of partial substitution of manganese by iron on the physical properties of Pr_0.6Ca_0.1Sr_0.3Mn_1−xFe_xO₃ (0 ⩽ x ⩽ 0.075) were investigated experimentally. Our samples were synthesized using the Pechini sol–gel method. X-ray diffraction analysis shows that our compounds crystallize in the orthorhombic structure with the Pbnm space group. Magnetic measurements show that all our materials exhibit a paramagnetic–ferromagnetic transition with decreasing temperature. The M(T) curves at μ₀H = 0.05 T indicate a monotonic drop in the Curie temperature (T_C) from 270 K for x = 0.0–112 K for x = 0.075 as the Fe concentration is increased. The results of electrical resistivity versus temperature measurements show that all our samples exhibit a metallic behavior at low temperature. For higher values of temperature, metal–insulator transition is seen at temperature T_p. From isothermal magnetization versus magnetic applied field, we deduced the magnetic entropy change ΔS_M. The maximum values of the magnetic entropy change (-ΔS_M^max) at 5 T applied change in the magnetic field are 3.64 and 3.12 J/kg K for x = 0 and x = 0.075 samples respectively. Under an applied magnetic field of 5 T, the relative cooling power (RCP) values are found between 243 and 256 J/kg for undoped sample and x = 0.075 respectively. Our results are interesting enough and suggest that these materials may be suitable candidates as working substances in magnetic refrigeration