Effect of the partial substitution of Fe on the magnetic properties of new brownmillerite oxides LaSrMn 2−x Fe x O 5 (0≤ x ≤0.5)

The present study investigates the effects of the substitution of iron in the B-site on the magnetic and magnetocaloric properties of the new brownmillerite LaSrMn2O5 powder. Our samples were synthesized using the conventional solid state reaction at high temperature. Magnetization measurements versus temperature in an applied magnetic field of 0.05T indicated that the samples underwent a paramagnetic-ferromagnetic transition with decreasing temperature. The Curie temperature TC decreased with more substitution of iron content. Arrott plots showed that all samples exhibited a second order magnetic phase transition. Magnetocaloric effect was calculated in terms of isothermal magnetic entropy change. A large magnetocaloric effect was observed for x=0.1 and x=0.2 samples. The maximum magnetic entropy changes, |ΔSMMax|, obtained were 0.7Jkg−1K−1 and 0.75Jkg−1K−1 in magnetic field change of 5T for x=0.1 and x=0.2, respectively.