Critical behavior of Nd0.67Ba0.33Mn1−xFexO3 (x=0 and 0.02) manganites

We used Banerjee’s criteria, modified Arrott plots and scaling hypothesis to analyze magnetic-field dependences of magnetization near the ferromagnetic–paramagnetic (FM–PM) phase-transition temperature (TC) of Nd0.67Ba0.33Mn1−xFexO3 (x=0 and 0.02) manganites. Experimental results reveal that the two samples undergo a second-order phase transition and a critical exponents values (β=0.326±0.005, γ=1.244±0.033, δ=4.740 at TC=145 K for x=0 and β=0.509±0.013, γ=1.140±0.117 and δ=3.011 at TC=134 K for x=0.02) slightly shifting from those of the 3D-Ising model and the mean field model, respectively. These exponents indicate that the exchange interaction J(r) ranges from r−5 and r−4.5 for x=0 (respectively J(r)