Magnetic anisotropy and superparamagnetism in La0.6Ca0.4MnO3, La0.6Sr0.4MnO3 and their mixed composition 0.875 La0.6Ca0.4MnO3/0.125 La0.6Sr0.4MnO3, agglomerated at different temperatures

The static magnetic properties of nano-particles La0.6Ca0.4MnO3 (S0C1), La0.6Sr0.4MnO3 (S1C0) and the 0.875(S0C1)0.125(S1C0) composition sintered at different temperatures, SC. 4-1 (700 °C), SC. 4-2 (900 °C), SC. 4-3 (1100 °C) and SC. 4-4 (1300 °C), have been investigated by the dc magnetic susceptibility, FC and ZFC magnetization, isothermal magnetization M(μ0H, 5 K) measurements and hysteresis loop at different temperatures. The nano-metric size of the studied compounds, determined by using the Scherrer formula and partially supported by TEM images, is at the origin of superparamagnetism phenomenon encountered in the compounds studied below the Curie temperature. The evolution of the Curie temperature is explained by the cationic disorder in A-site. To explain the difference between the theoretical and experimental values of the magnetization saturation, it has been adopted the Core-shell model.