J. Phys. IV France
Volume 123, March 2005
Page(s) 413 - 418

J. Phys. IV France 123 (2005) 413-418

DOI: 10.1051/jp4:2005123076

The effect of cation radii on structural, magnetic and electrical properties of doped manganites La0.6-xPrxSr0.4MnO3

S. Zemni1, Ja. Dhahri1, J. Dhahri1, M. Oumezzine1 and H. Vincent2

1  Laboratoire de Physico-Chimie des Matériaux, Faculté des Sciences de Monastir, Département de Physique, 5019 Monastir, Tunisie
2  Laboratoire des Matériaux et de Génie Physique, ENSPG, BP. 46, 38402 Saint-Martin d'Hères Cedex, France

The effect of trivalent substitution into rare earth sites in La $_{0.6\hbox{-}{\rm x}}$Pr$_{\rm x}$Sr0.4MnO3 oxides has been studied. The structural, and magnetic properties of these compounds with a fixed Mn3+/Mn4+ ratio of 3/2 are studied. X-ray diffraction patterns show that these compounds are rhombohedral (R $\bar{\bf 3}$ c) below x = 0.42 and become orthorhombic (Pbnm) above x = 0.42. The paramagnetic to ferromagnetic transition temperature T$_{\rm C}$ decrease from 374K to 310K when < r$_{\rm A}$ > decreases. The ionic radii variance $\sigma^{2}$ decreases with the increase of < r$_{\rm A}$ >. The resistivity transition temperature T$_{\rho}$ decreases from 350 K to 280 K as Pr content increases.

Key words: Perovskite, Manganite, Cation size.

© EDP Sciences 2005