Phase separation scenario in Ba doped LaMnO 3

Polycrystalline bulk samples of La1–XBaXMnO3 (x = 0.5 – 0.65) were synthesized by solid state reaction route. Low temperature four probe resistivity measurements and a.c. susceptibility measurements were carried out on these samples after the analysis of powder XRD data with Rietveld fitting method. All the studied compounds showed paramagnetic to ferromagnetic transition at TC ∼ 330 K and also showed insulator-metal transition (at temperature TP) with no indication of charge-ordering. In La1−xBaxMnO3 case the insulator-metal transition is well below the magnetic transition. At x = 0.55, the difference in TP and TC is ∼ 90 K and also XRD pattern starts showing the existence of BaMnO3 phase which grows with x. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)