Eur. Phys. J. B 24, 419-423 (2001)
https://doi.org/10.1007/s10051-001-8693-2

Ferromagnetism in lacunar perovskite manganites Pr_0.7Sr_{0.3-x x}MnO₃ and Pr_{0.7-x x}Sr_0.3MnO₃

¹ Laboratoire de Physique des Matériaux, Faculté des Sciences de Sfax, BP 802, 3018 Sfax, Tunisia
² Laboratoire des Matériaux et du Génie Physique (ENSPG-CNRS (UMR-5628)) , BP 46, 38402 Saint Martin d'Hères Cedex, France

Corresponding author: ^a Abdel.Cheikhrouhou@fss.rnu.tn

Received: 12 April 2000
Revised: 8 January 2001
Published online: 15 December 2001

Abstract

Deficiency effects in the A site upon the structural, magnetic and electrical properties in the lacunar perovskite manganite oxides Pr_0.7Sr _xMnO₃ () and Pr _xSr_0.3MnO₃ () have been investigated. This study focuses on the different parameters which govern the magnetic and electrical properties in such samples. The powder X-ray diffraction patterns for all samples could be indexed either with a rhombohedral perovskite structure and Rc space group for in strontium deficient samples and for for praseodymium deficient ones. For other values of x the samples could be indexed in the orthorhombic structure with Pbnm space group. Magnetic and electrical investigations show that praseodymium and strontium vacancies do not have similar effects on the lacunar compounds. Magnetization measurements versus temperature show that all our samples exhibit a magnetic transition when the temperature decreases. All the praseodymium deficient samples exhibit a paramagnetic-ferromagnetic transition when the temperature decreases while the strontium deficient ones exhibit this transition only for low x values. The magnetic transition temperature shifts to lower values as the strontium deficiency increases (from 265 K for x = 0 to 90 K for x = 0.3) and to higher values with the praseodymium deficiency increase (from 265 K for x = 0 to 315 for x = 0.23). Resistivity measurements as a function of temperature show a semiconducting-metallic transition for all x values in the praseodymium lacunar samples and only for low x values () in the strontium lacunar ones when the temperature decreases.