Critical parameters near the ferromagnetic-paramagnetic phase transition in La0.5Ca0.5-xAgxMnO3 compounds (0.1 x 0.2)

Smari M. (1) , Walha I. (1) , A. Omri (1) , Jean-Jacques Rousseau (2) , E. Dhahri (1) , El-Kebir Hlil (3)

1 LPA - Laboratoire de Physique Appliquée [Université de Sfax]
2 LT2C - Laboratoire Telecom Claude Chappe
3 NEEL - MagSup - Magnétisme et Supraconductivité

The critical properties of mixed manganite La0.5Ca0.5 xAgxMnO3 (x = 0.1 and 0.2) around the paramagnetic-ferromagnetic phase transition are investigated through various techniques such as modified Arrott plot, Kouvel-Fisher method, and critical isotherm analysis. The magnetic data analyzed in the critical region using the above methods yield the critical exponents for (x = 0.1) La0.5Ca0.4Ag0.1MnO3 ( =0.311 ± 0.003 and =1.146 ± 0.006 at TC = 226.27 ± 0.02 K). Moreover, the estimated critical exponents of (x = 0.2) La0.5Ca0.3Ag0.2MnO3 are ( = 0.288 ± 0.002 and = 0.948 ± 0.008 at TC = 262.31± 0.06). The values deduced for the critical exponents are closed to the theoretical prediction of 3D-Ising model and tri-critical mean-field model. These results suggest that the present composition should be close to a tricritical point in the La0.5Ca0.5 xAgxMnO3 phase diagram.

Domaines: Sciences de l'ingénieur [physics]

Smari M., Walha I., A. Omri, Jean-Jacques Rousseau, E. Dhahri, et al.. Critical parameters near the ferromagnetic-paramagnetic phase transition in La0.5Ca0.5-xAgxMnO3 compounds (0.1 x 0.2). Ceramics International, 2014, 40 (7), pp.8945-8951. ⟨10.1016/j.ceramint.2014.01.142⟩. ⟨hal-00959432⟩