Evolution of crystal structure with the oxygen content in the LaMn0:9Cr0:1O3þd ð3:00p3 þ dp3:12Þ compound

L. MORALES; A. CANEIRO

JOURNAL OF SOLID STATE CHEMISTRY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2003 vol. 170 p. 404 - 410

0022-4596

We report the structural evolution as a function of oxygen content for LaMn0:9Cr0:1O3þdð3:00p3 þ dp3:12Þ in samples preparedwith accurate control of the oxygen content. The relationship between the structural parameters and magnetic behavior isestablished using d as control parameter. As the d value increases, three different orthorhombic regions are found: for dodc thedistorted O0 phase ðb= ffi2ffiffip ocoaÞ; and for d40:06 two low distorted orthorhombic regions (O00 with b= ffi2ffiffip oaoc and O00 0 withaob= ffi2ffiffip oc). The structural study shows a critical fcE111 tilt angle corresponding to dcE3:06 and is related to a jump in thecritical temperature and magnetic moment ðmÞ: This fc separates FM from non-FM samples. The results are compared with thosefor LaMnO3þd: The variation of m as a function of oxygen content and therefore with the amounts of Mn4þ allowed us to discuss therole of the Cr3þ ion on the magnetic behavior of LaMn0:9Cr0:1O3þd: