Crystal structure and magnetic ordering of the LaCo1−xFexO3system

The LaCo1−xFexO3 compounds have been investigated by means of neutron powder diffraction (NPD), x-ray powder diffraction (XPD) and magnetization measurements. The NPD and XPD patterns were successfully refined as rhombohedral (x≤0.5) and orthorhombic (x≥0.6). The temperature-induced transition from the rhombohedral phase into the orthorhombic one is characterized by a two-phase crystal structure state. Magnetization and neutron powder measurements have revealed that compounds with x<0.4 exhibit a paramagnetic-like behaviour, whereas for x≥0.4 samples a weak ferromagnetic component was observed. The NPD patterns were successfully refined by admitting a Gz spatial orientation of the antiferromagnetic vector. The magnetic properties of the LaCo1−xFexO3 samples can be explained assuming a low spin state of the Co3+ ions, whereas antiferromagnetism is caused by magnetic interactions between the Fe3+ ions. Based on the obtained data the combined crystal and magnetic phase diagram has been constructed.