Neutron powder diffraction study of the nuclear and magnetic structures of LaMn1xCrxO3:00 (x = 0:05, and 0.15))

L. MORALES; A. CANEIRO; M. JAMES

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Año: 2006 vol. 385 p. 415 - 417

0921-4526

A comparative study of the nuclear and magnetic structures of LaMn1xCrxO3:00 perovskite (x ¼ 0:05, and 0.15) is reported. Cr3þ isisoelectronic with Mn4þ ð3d3Þ and is also a non-Jahn?Teller ion. Both magnetic ions increase the hole (empty eg levels) concentration anddecrease the Jahn?Teller distortion. To characterize the interaction established between Mn3þ and Cr3þ and the effect of Cr3þ on themagnetic structure, samples without Mn4þ were synthesized. X-ray powder diffraction, at room temperature, reveals the existence ofsingle phase materials with orthorhombic symmetry (Pnma) for all the studied samples. Magnetic data shows an increase of the FMinteraction with Cr content. Magnetic phases change from A-type antiferromagnetic order to a system with magnetic clusters through aspin-glass-like phase. In order to fully understand the magnetic phase diagram, neutron powder diffraction was carried out. Both,nuclear and magnetic structures are studied as a function of temperature and Cr content. These results reveal the presence of more thanone magnetic phase and a clear change of the spin orientation with temperature and Cr content. The mixture of magnetization andneutron powder diffraction data allow us to describe the role of the Cr3þ on the magnetic properties.