# Molten salt-directed catalytic synthesis of room-temperature ferromagnetic transition-metal nitride nanosheets

## TL;DR

A new method creates ultrathin molybdenum nitride nanosheets that show strong magnetism at room temperature, promising for future electronic devices.

## Contribution

A three-step molten salt-directed catalytic method to synthesize intrinsic room-temperature ferromagnetic γ-Mo2N nanosheets.

## Key findings

- γ-Mo2N nanosheets show ferromagnetism with a Curie temperature of about 360 K.
- Ferromagnetism is attributed to 4d electrons of Mo atoms with itinerant characteristics.
- Extensive characterization confirms structural stability and absence of magnetic impurities.

## Abstract

The next generation of low-power electronic/spintronic devices based on two-dimensional (2D) magnetic materials has great application prospects. However, so far, the numbers of intrinsic room-temperature magnetic 2D materials is limited. Here, we report a simple and effective three-step molten salt-directed catalytic method for obtaining intrinsic room-temperature ferromagnetic gamma-Mo2N (γ-Mo2N) nanosheets. The γ-Mo2N nanosheets with high crystallization and ultra-thin 2D layered structure characteristics show obvious ferromagnetism and Curie temperature (Tc) up to about 360 K. Meanwhile, ICP-AES measurement excludes the possibility of ferromagnetic impurities. Extensive synchrotron radiation X-ray absorption fine structure (XAFS) spectra characterizations confirm the bonding configuration of Mo–N coordination around Mo atoms as well as the structural stability of the samples. Detailed spin-polarized density functional theory (DFT) calculations reveal that ferromagnetism of γ-Mo2N nanosheets is mainly contributed by 4d electrons of Mo atoms with itinerant electron characteristics. This work highlights γ-Mo2N nanosheets as a promising intrinsic room-temperature ferromagnetic material for the development of spintronics or spin-based electronics.

We report a facile molten-salt strategy to synthesize ultrathin γ-Mo2N nanosheets, which exhibit intrinsic room-temperature ferromagnetism. This work establishes transition metal nitrides as a new class of 2D magnetic materials for spintronics.