Interstitial nitrogen-modified Y2Fe16SiNy compounds towards enhanced high-frequency magnetic properties.

The rapid development of information technology urgently requires high-frequency soft magnetic materials with excellent electromagnetic performance. Herein, we synthesized the disordered dual-phase Y 2 Fe 16 Si intermetallic compound and introduced nitrogen atoms into its interstitial crystal sites by the gas-solid reaction, remarkably improving its magnetic and electromagnetic properties. The significant magneto-volume effect generated by introduced nitrogen atoms increases the compound's magnetization and Curie temperature, leading to increased permeability of Y 2 Fe 16 Si-paraffin composites. Furthermore, the synergistic effect of the magneto-volume and the chemical bonding change the compound's electric polarization by charge neutralization, dramatically decreasing the permittivity of Y 2 Fe 16 Si-paraffin composites upon nitrogenation. The decreased permittivity and increased permeability enhance the impedance matching and magnetic loss capability of the composites. Besides, the introduction of interstitial nitrogen gives rise to a higher ratio of the out-of-plane to in-plane anisotropy field of Y 2 Fe 16 Si due to anisotropic lattice expansion, which combines with enhanced magnetization to raise the Snoek limit and operating frequency of the composites. Consequently, Y 2 Fe 16 SiN y -paraffin composites exhibit the maximum effective absorption bandwidth (EAB) of 5.84 GHz in a thickness of 1.2 mm, and the minimum reflection loss (RL min) of –50.52 dB in a thickness of 1.5 mm covering the Ku -band, demonstrating strong absorption, broad EAB with thin thickness and high operating frequency. This work shows the superiority of the interstitial atom effect in the high-frequency electromagnetic field, and the effect is applicable and scalable for rare-earth Fe-based intermetallic compounds to develop excellent microwave absorbers. [Display omitted] [ABSTRACT FROM AUTHOR]