Variation between Antiferromagnetism and Ferrimagnetism in NiPS3 by Electron Doping

TL;DR

This study demonstrates how electron doping via organic cation intercalation can reversibly switch magnetic order in NiPS3 from antiferromagnetic to ferrimagnetic and back, revealing a new control method for 2D magnetic materials.

Contribution

It introduces a defect-free doping method to tune magnetic phases in NiPS3, revealing the competition between different magnetic interactions at various doping levels.

Findings

Doped NiPS3 transitions from AFM to FIM at 0.2-0.5 electrons/cell.

Further doping causes FIM to revert to AFM at >= 0.6 electrons/cell.

The magnetic phase change is due to competition between Stoner exchange and super-exchange interactions.

Abstract

How to electrically control magnetic properties of a magnetic material is promising towards spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, we found electron doping dependent variation of magnetic orders of a two-dimensional (2D) AFM insulator NiPS3, where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS3 without introduction of defects and impurity phases. The doped NiPS3 shows an AFM-ferrimagnetic (FIM) transition at doping level of 0.2-0.5 electrons/cell and a FIM-AFM transition at doping level of >= 0.6 electrons/cell. We propose that the found phenomenon is due to competition between Stoner exchange dominated inter-chain ferromagnetic order and super-exchange dominated inter-chain AFM order at different doping level. Our studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect.