Critical behavior in Fe-doped manganites La0.8Ba0.2Mn1−xFexO3 (x = 0.15 and x = 0.2)

• Results show that the paramagnetic–ferromagnetic transition is of second order.
• Critical exponents for AMnO3 are close to those for the 3D-Heisenberg.
• Effective exponent is similar to those for disordered ferromagnets.
• The obtained critical exponents fulfill Widom scaling relation.

The critical properties of La0.8Ba0.2Mn1−xFexO3 polycrystalline samples near ferromagnetic–paramagnetic phase transition temperature have been investigated by analyzing isothermal magnetization data. Experimental results revealed that all samples exhibit a second-order magnetic phase transition. Dc-magnetization data near the transition temperature have been analyzed with the help of the modified Arrott plot, Kouvel–Fisher method. The value of critical exponents, derived from the magnetization data using the Kouvel–Fisher method, yield 0.370 ± 0.02 ⩽ β ⩽ 0.379 ± 0.01, 1.359 ± 0.02 ⩽ γ ⩽ 1.392 ± 0.03 and 4.40 ± 0.0 ⩽ δ ⩽ 4.67 ± 0.01with a TC of 125 ± 0.02–157.50 ± 0.02 K. The exponent values are close to those expected for three-dimensional (3D) Heisenberg ferromagnets which is short-range magnetic interaction.