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Pressure-induced modifications of crystal and magnetic structure of oxygen deficient La0.7Sr0.3MnO3-d manganites

Research paper by D. P. Kozlenko, S. V. Trukhanov, E. V. Lukin, I. O. Troyanchuk, B. N. Savenko

Indexed on: 14 Sep '07Published on: 14 Sep '07Published in: The European Physical Journal B



Abstract

The crystal and magnetic structures of the oxygen deficient manganites La0.7Sr0.3MnO3-d (d = 0.15, 0.20) have been studied by means of powder neutron diffraction over the 0–5.2 GPa pressure and 10–290 K temperature ranges. La0.7Sr0.3MnO2.85 exhibits a coexistence of rhombohedral \((R\bar {3}c)\) and tetragonal (I4/mcm) crystal structures and below Tg ~ 50 K a spin glass state is formed. La0.7Sr0.3MnO2.80 exhibits a tetragonal (I4/mcm) crystal structure. Below Tg ~ 50 K a phase separated magnetic state is formed, involving coexistence of C-type AFM domains with spin glass domains. In both compounds the crystal structure and magnetic states remain stable upon compression. The factors leading to the formation of different magnetic states in La0.7Sr0.3MnO3-d (d = 0.15, 0.20) and their specific high pressure behavior, contrasting with that of the stoichiometric A0.5Ba0.5MnO3 (A = Nd, Sm) compounds showing pressure-induced suppression of the spin glass state and the appearance of the FM state, are analysed.