Deficiency effects upon the physical properties of Pr0.8Sr0.2MnO3 manganite oxide

The effects of deficiency in praseodymium and in strontium upon the magnetic and magneto-transport properties of lacunar Pr0.8–x□xSr0.2MnO3 and Pr0.8Sr0.2–x□x MnO3 oxides have been investigated. Our synthesized samples have been elaborated using the conventional solid state reaction at high temperature. Crystallographic studies show that all our samples are single phase and crystallize in the orthorhombic system with Pnma space group. The praseodymium deficient samples Pr0.8–x□xSr0.2MnO3 exhibit three different regimes in the resistivity variation as a function of praseodymium deficiency amount: (i) at low concentration (0 ≤ x ≤ 0.1), a semiconductor behaviour is observed in the whole temperature range, (ii) at an intermediate amount (x = 0.15), a semiconductor-metallic transition is followed by a metallic-semiconductor one with decreasing temperature, and finally (iii) at x = 0.2 and 0.25, a metallic behaviour is observed below TC, whereas all the strontium deficient samples exhibit a semiconductor behaviour in the whole temperature range. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)