Investigation of spin-orientation in antiferromagnetic ordering for LiFe1-xZnxPO4 with Mössbauer spectroscopy

Hyunkyung Choi,Mun Hwan Kim,Chul Sung Kim

doi:10.1063/1.5042846

Abstract

We have investigated the spin orientation in antiferromagnetic polycrystalline LiFe1-xZnxPO4 using Mössbauer spectroscopy. The temperature-dependent magnetic susceptibility curves show antiferromagnetic behavior with ordering temperature. The experimentally determined effective moment of LiFe1-xZnxPO4 is larger than the theoretical value, which can be explained as incomplete absence of orbital contribution by the crystalline field around distorted octahedra. The value of the Néel temperature (TN) and the spin reorientation temperature (TS) of LiFe1-xZnxPO4 decreased with the increasing Zn concentrations from 48 and 14 K for x = 0.1 to 36 and 8 K for x = 0.5, resulting in weak antiferromagnetic interaction. Below TN, Mössbauer spectra of LiFe1-xZnxPO4 showed asymmetric eight-line shape due to the strong crystalline field in the distorted octahedral structure. A change in both the magnetic hyperfine field and electric quadrupole splitting below TS suggests that magnetic phase transition is related to the spin rotation and the superexchange interaction.

Highlights

Modern electrochemical systems are considered for critical environmental, technical, and commercial use, with wide application in green energy storage device.[1,2,3] Lithium-ion batteries have high energy, power density, and excellent cycling performances.[4,5] Among these compounds, olivine phosphate materials have attracted attention as promising cathode candidates
To obtain understanding of the Zn doping effects LiFePO4, we studied the effect of Zn doping on the structure and magnetic properties of LiFePO4
The magnetic susceptibility curves were carried out using a vibrating sample magnetometer (VSM)

Summary

Introduction

Modern electrochemical systems are considered for critical environmental, technical, and commercial use, with wide application in green energy storage device.[1,2,3] Lithium-ion batteries have high energy, power density, and excellent cycling performances.[4,5] Among these compounds, olivine phosphate materials have attracted attention as promising cathode candidates. There are major drawbacks, such as low lithium-ion mobility and poor electronic conductivity. To overcome these drawbacks, the effects of Zn-doped LiFePO4 have been studied. It was reported that the divalent cations could sustain the lattice after lithium ion extraction from cathodes.[6,7] Many research groups reported improved electron conductivity and increased charge/discharge capacity with Zn-doping.[8,9]

Methods

Results

Conclusion