Discontinuous Evolution of the Highly Distorted Orthorhombic Structure and the Magnetic Order in LaMnO3±δ Perovskite

PRADO, F.; SÁNCHEZ, R.D.; CANEIRO, A.; CAUSA, M.T.; TOVAR, M.

JOURNAL OF SOLID STATE CHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1999 vol. 146 p. 418 - 427

0022-4596

In this work we present a systematic study of the crystallographic structure and the magnetic ordering of LaMnO3±δ perovskites. Changing the oxygen composition within the range 2.995<3±δ<3.140, we found a 3+δ1 value (3.04<3+δ1<3.05) which defines a boundary in the magnetic phase diagram T vs 3±δ. For 3+δ<3+δ1, antiferromagnetic order is present in the samples with a small ferromagnetic component, while for large 3+δ values (3+δ>3+δ1) the samples are ferromagnetic. The transition from one region to the other is associated with a change in volume of around 1%.