Structural and magnetic properties of LiCrO2

Abstract

Two-dimensional antiferromagnetic systems have attracted the re search community because of their multiferroic behaviour. Here, we study the structural and magnetic properties of LiCrO2 and doped compounds LiCr1−xMxO2 with x =0.01 and0.05 (where M=Fe, Mn)andLi1−xMxCrO2 with x=0.01 (M = Cu). All these samples were synthesized using the con ventional solid-state reaction method. From XRD we are confirming the single-phase rhombohedral crystal structure. The expansion of the lattice along c- axis was observed in all compounds. From Raman spectroscopy measurement, two Raman modes A1g and Eg are found in all the com pounds. Temperature dependent Raman spectra were also studied in the range, 200 K to 350 K. We have not observed any anomalies and structural phase transition within this temperature range. The antiferromagnetic transition temperature, TN ≈ 54.8 K, was observed by recording the ac susceptibility of LiCrO2 using a AC magnetic susceptibility measurement system, integrated in the Quantum Design Physical Properties Measure ment System (PPMS). Measurement carried out at a constant frequency of 3337 Hz. The Neel temperature of all the doped samples shift towards the higher temperature indicating the release of magnetic frustration due to minor doping. From UV-Vis spectroscopic measurements, the energy band gap of all the compositions was determined. The parent compound seems to have a band gap of 1.57 eV. After doping energy band gap of compounds reduces as the ionic radius of the dopant cation increases.