Effect of strontium deficiency on the critical behavior at paramagnetic to ferromagnetic phase transition in La0.57Nd0.1Sr0.33MnO3 manganite oxide

The samples of manganese perovskite La0.57Nd0.1Sr0.33−xxMnO3 (0.00 ≤ x ≤ 0.05) ( is the strontium deficiency) are prepared by solid-state methods, and all of them have a rhombohedral perovskite structure, revealed by X-ray diffraction. The critical properties of the samples around the paramagnetic–ferromagnetic phase transition were investigated through various techniques such as modified Arrott plot (MAP), Kouvel–Fisher (KF) method and critical isotherm (CI) analysis based on the data of static magnetic measurements recorded around the Curie temperature TC. The experimental results have revealed that the samples exhibited the second-order magnetic phase transition and the critical exponents of β and γ for La0.57Nd0.1Sr0.33MnO3 are close to those found out by the 3D-Heisenberg model. Furthermore, the estimated critical exponents of La0.57Nd0.1Sr0.33−xxMnO3 (x = 0.025 and 0.05) are consistent with the prediction of the 3D-Ising model. We deduced, following the Harris criterion, that the disorder in our case is relevant which can be the cause of the change in the universality class and we noted that the critical exponents β are almost similar to the value of the mean-field theory which can be explained by the existence of a long-range dipole–dipole interaction.

Scaling plot below and above TC using the β and γ exponents determined from Kouvel–Fisher method of La0.57Nd0.1Sr0.33−xxMnO3 for x = 0.05.Figure optionsDownload as PowerPoint slide