Effect of oxygen non-stoichiometry on the structural and magnetotransport properties of LaMn0.85Cr0.15O3+δ

L.B. MORALES; R. ZYSLER; A. CANEIRO

JOURNAL OF SOLID STATE CHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2008 vol. 181 p. 1824 - 1832

0022-4596

Thermogravimetry, X-ray diffraction (XRD), d.c. magnetization, high-temperature susceptibility and electrical resistivity measurements were performed for LaMn0.85Cr0.15O3+δ perovskites with accurate control of the oxygen content (0≤δ≤0.11). For 0≤δ<0.09, three orthorhombic structures (Pnma) are found: for 0≤δ<0.045, the O′ phase (b/√2<c<a), for 0.045≤δ<0.06, the O″ (b/√2<a<c) and for 0.06≤δ<0.09, the O‴ (a<b/√2<c). For 0.09≤δ≤0.11, a rhombohedral symmetry (R over(3, -) c) coexists with O‴ in a biphasic field. Magnetic measurements revealed the ferromagnetic interactions (FM) character of the Mn3+-O-Cr3+ interaction, but also the intricate magnetic phase diagram due to the presence of multiple interactions (Mn3+,4+-O-Mn3+,4+, Cr3+-O-Mn3+, etc.). The comparison of the results for LaMn0.85Cr0.15O3+δ with those of LaMn0.9Cr0.1O3+δ allows discuss the role of Cr3+ on the structural, magnetic and magnetotransport properties of the LaMn1-xCrxO3+δ perovskites.