화학공학소재연구정보센터
Journal of Materials Science, Vol.49, No.20, 6883-6891, 2014
Critical behavior in Fe-doped manganites La0.67Ba0.22Sr0.11Mn1-xFexO3 (0 <= x <= 0.2)
The critical properties of the manganese perovskite La0.67Ba0.22Sr0.11Mn1-x Fe (x) O-3 (0 <= x <= 0.2) around the paramagnetic (PM)-ferromagnetic (FM) phase transition were investigated using modified Arrott plots and Kouvel-Fisher method based on the data of static magnetic measurements recorded around the curie temperature T (C). Based on the evaluated critical exponents for the compounds with different x values (0.378 <= beta <= 0.411, 1.247 <= gamma <= 1.393, and 4.018 <= delta <= 4.73) we concluded that the PM-FM phase transition in the compound with x = 0 belongs to the three-dimensional Heisenberg universality. However, the substitution of Fe3+ for Mn3+ resulted in shifting the value of gamma toward the 3D-Ising model value and a slight increase in beta. This behavior was discussed and correlated with the random distribution of Fe3+ at the Mn3+ sites and the consequent suppression the double exchange interaction.