Dilution Effects on Chemical and Magnetic Clusters of α-LiFeO₂

Abstract

We have synthesized -LiFe 1Àx In x O 2 (x ¼ 0, 0.001, 0.01, 0.05, and 0.1) powders by calcination of Li 2 CO 3 , Fe 2 O 3 and In 2 O 3 mixtures. In X-ray diffraction, the sample with larger x value showed larger lattice constant of the cubic NaCl-type structure. Aside from electron diffraction patterns of the cubic unit cell with diffuse scattering for both the samples, the x ¼ 0 sample demonstrated a doubled structure of the cubic unit cell with wavy diffuse scattering, though the x ¼ 0:1 sample exhibited the doubled structure with less intensive diffuse scattering. In cooling history-dependent dc susceptibilities, the bifurcation point of the x ¼ 0 sample was %90 K, and it lowered from 87 to 44 K with increasing the x value from 0.001 to 0.1. Dilution of -LiFeO 2 with nonmagnetic In 3þ ions suppressed chemical cluster formation at room temperature and reduced temperature of ferromagnetic cluster formation.

Transmission electron microscopy and electron diffraction study of the short-range ordering structure of α-LiFeO2

“…The magnetic lattice structure has a doubled lattice constant compared with the phase. Furthermore, an anomaly of magnetization at 40 K has been observed (Anderson et al, 1965;Tabuchi et al, 1998;Kohiki et al, 2004). It is expected that the anomalies are related to cation ordering, but the origin is not clear.…”