Magnetocaloric behavior in perovskite manganites La0.7A0.3Mn0.9Fe0.1O3 (A = Sr, Pb, Ba)

• Fe ionic valence in La0.7A0.3Mn0.9Fe0.1O3 is ascertained by Mössbauer spectroscopy.
• Magnetocaloric behavior of Fe3+ dopant in La0.7A0.3Mn0.9Fe0.1O3 is investigated.
• Correlation between magnetocaloric effect and crystal structure is established.

A comparative study is presented on magnetocaloric behavior in iron doped manganites La0.7A0.3Mn0.9Fe0.1O3 (A = Sr, Pb, Ba) prepared by a sol–gel technique and with Fe valence ascertained by the Mössbauer spectroscopy. For La0.7Sr0.3Mn0.9Fe0.1O3 sample, the maximum entropy change ΔS corresponding to a magnetic field variation of 1 T is found to be −0.82 J/kg K at 260 K resulting in a refrigerant capacity of 60 J/kg. The obtained results suggest that B-site Fe dopant actually disfavors the enhancement of the magnetocaloric effect in some perovskite manganites due to a weakening of the ferromagnetic double-exchange interaction between Mn3+ and Mn4+ ions of the original atomic structure.