Lithium iron oxide was found to be the most promising and very interesting materials due to their potential applications as a cathode for rechargeable lithium batteries and also due to low cost and toxicity [1-3]. Lithium iron oxide LiFeO₂ has NaCl type cubic closed packed (ccp) crystal structure with Li⁺ and Fe³⁺ being distributed in octahedral sites. LiFeO₂ crystallizes in different polymorphic modifications (α, β, γ) based on the synthesis techniques and preparation conditions [4-6]. The unit cell of α-LiFeO₂ has cubic distorted form with space group Fm3m. In α-LiFeO₂ structure, Li⁺ and Fe³⁺ ions occupy randomly the octahedral sites [7]. γ-LiFeO₂ structure is tetragonal cation disordered. Li⁺ and Fe³⁺ in the octahedral sites transform from cubic structure (Fm3m) to tetragonal (I4/m) structure [8]. In the case of monoclinic β-LiFeO₂ the cation ordering was detected [5,8]. It was observed that synthesis of LiFeO₂ is a difficult task as several phases are associated during preparation process. Earlier LiFeO₂ have been synthesized by different techniques such as hydrothermal [6,9], citrate precursor method [10], solid state reaction [11], ion exchange reaction [12] etc. and observed different polymorphic phases and improved structural and electrical properties. In this paper we made an attempt to synthesize nanocrystalline LiFeO₂ using sol-gel method. To clearly understand the structural formation and the corresponding phases of LiFeO₂ and the underlying magnetic properties we have carried the present work.

The LiFeO₂ nanoparticles have been synthesized by sol-gel method [13]. The AR grade citric acid (C₆H₈O₇·H₂O), ferric nitrate (Fe(NO₃)₃·9H₂O) and lithium nitrate (LiNO₃) (≥99%) were used as starting materials. The entire synthesis procedure is described elsewhere [13]. The as prepared powder samples were sintered at 500˚C for 5 h.

Crystallographic structure of LiFeO₂ nanopowder was measured using Philips PW 3020 Bragg-Brentano diffractometer using Cu Kα radiation (wave length λ = 1.54 Å). The morphology of powder was observed using scanning electron microscopy (SEM) from Carl Zeiss. Room temperature magnetization was measured using ADE magnetics DMS 4 Vibrating Sample Magnetometer (VSM).

Figure 1 shows (a) experimental and (b) calculated X-ray diffraction patterns of nanocrystalline LiFeO₂. Crystal structures of different phases present in the