Structure and Magnetic Properties of ${\hbox {LiFePO}}_{4}$ Under Pressure

LiFePO₄ has attracted considerable attention as cathode materials for rechargeable lithium batteries. Here, the structural, electronic, and magnetic properties of LiFePO₄ under pressure are investigated based on density functional theory. When pressure is applied to the LiFePO₄, a transition to a Cmcm phase is identified, agreeing well with experimental results. Upon compression, the magnetic moment of Fe ion decreases steadily without abrupt change, being different from iron nitride. With increasing pressure the band broadening induces the spin flipping, which consequently results in the lower magnetic moment of Fe ion. By further applying pressure LiFePO₄ undergoes magnetic transition from antiferromagnetic state to nonmagnetic state at 52 GPa. Hence pressure can be used as efficient way to manipulate even eliminate the magnetism of LiFePO₄.