Effect of calcium deficiency on the critical behavior near the paramagnetic to ferromagnetic phase transition temperature in La0.8Ca0.2MnO3 oxides

► Critical exponents for La0.8Ca0.2MnO3 are close to those for the 3D-Ising model. ► La0.8Ca0.1□0.1MnO3 sample belongs to the 3D-Heisenberg universality class. ► The disorder is relevant following the Harris criterion. ► The change in the universality class is due to the dipole-dipole interaction.