Ferromagnetic short-range order and magnetocaloric effect in Fe-doped LaMnO3

We have studied the critical behavior and magnetocaloric effect of a perovskite-type manganite LaMn0.9Fe0.1O3 with a second-order phase transition. Detailed critical analyses based on the modified Arrott plot method and the universal scaling law gave the critical parameters TC≈135.7 K, β=0.358±0.007, γ=1.328±0.003, and δ=4.71±0.06. Comparing to standard models, the critical exponent values determined in our work are close to those expected for the 3D Heisenberg model (with β=0.365, γ=1.336, and δ=4.80). This reflects an existence of ferromagnetic short-range order in LaMn0.9Fe0.1O3. Around TC, the magnetic entropy change reaches the maximum value (ΔSmax), which is about 3.8 J·kg−1·K−1 for the applied field of 50 kOe. Particularly, its magnetic-field dependence obeys the power law |ΔSmax|∝Hn, where n=0.63 is close to the value calculated from the relation n=1+(β−1)/(β+γ).