Neutron diffraction study and magnetic properties of La_1−<i>x</i>Ba_<i>x</i>CoO₃(<i>x</i>= 0.2 and 0.3)

Abstract

The magnetic properties together with the crystal and magnetic structures of the cobaltites La(1-x)Ba(x)CoO(3) (for x = 0.2 and 0.3) are determined by DC magnetization, AC magnetic susceptibility and neutron powder diffraction measurements over a broad spectrum of temperatures. For x = 0.3 a rhombohedral structure with space group [Formula: see text] is maintained at all temperatures below 300 K. On the other hand, for x = 0.2 the refinement of the neutron data below 150 K indicates the coexistence of two structures, [Formula: see text] (rhombohedral) and Pbnm (orthorhombic), respectively, in a ratio of ∼48/52. Both compounds (x = 0.2 and 0.3) show a ferromagnetic long range order. The data fit well with the Co(3+) ions in the intermediate spin state and the Co(4+) ions in a low spin state.