Abstract
The critical bahaviour of La0.65Ce0.05Sr0.3Mn1xCuxO3 (x = 0, x = 0.05 and x = 0.15) manganite prepared by the sol-gel-based Pechini method has been investigated by measuring the magnetization around the Curie temperature, T-C. The obtained critical exponents (beta, gamma and delta) have been calculated using the modified Arrott plot and Kouvel-Fisher techniques, scaling hypothesis and critical isotherm analysis. The estimated results for the parent compound and x = 0.05 are in between mean-field and the 3D Heisenberg models. The values of beta, gamma and delta will shift gradually toward those of the 3D Heisenberg theory when x = 0.15, suggesting that the short-range FM order and magnetic inhomogeneity are favoured in Cu-doped samples. The non-monotonous temperature variation in effective exponents (beta(eff)(e) and gamma(eff)(e)) proves the existence of a magnetic disorder in the studied compounds.