Effect of the partial substitution of Fe on the magnetic properties of new brownmillerite oxides LaSrMn2−xFexO5 (0≤x≤0.5)

Abstract 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 LaSrMn 2 O 5 powder. Our samples were synthesized using the conventional solid state reaction at high temperature. Magnetization measurements versus temperature in an applied magnetic field of 0.05 T indicated that the samples underwent a paramagnetic-ferromagnetic transition with decreasing temperature. The Curie temperature T C 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, | Δ S M Max | , obtained were 0.7 J kg −1 K −1 and 0.75 J kg −1 K −1 in magnetic field change of 5 T for x =0.1 and x =0.2, respectively.