Transport phenomena in the compound: LiFe1/2Mn1/2VO4

The LiFe1/2Mn1/2VO4 was prepared by a standard solid-state reaction route. X-ray diffraction (XRD) study confirms the formation of the material under reported conditions and it reveals an orthorhombic unit cell structure with lattice parameter: a = 3.7111 Å, b = 15.6568 Å, c = 16.3478 Å. Complex impedance analysis of the sample indicates: (i) bulk contribution to electrical properties up to 125 °C, (ii) grain boundary effects for all T ≥ 130 °C, (iii) negative temperature coefficient of resistance (NTCR) effect and (iv) evidence of temperature dependent electrical relaxation phenomena in the material. D.c. conductivity (σdc) shows typical Arrhenius behavior when observed as a function of temperature. The activation energy values were estimated to be ~ 0.53 eV (25-175 °C) and ~ 0.73 eV (175-475 °C) from temperature variation of d.c. conductivity. Modulus analysis has been carried out to understand the mechanism of electrical transport process and this indicates non-Debye type conductivity relaxation in the material.