Electronic structure and magnetic properties of R/sub 2/Fe/sub 17/N/sub x/

The author reviews the study of magnetism in R/sub 2/Fe/sub 17/ compounds based on self-consistent, spin-polarized electronic-structure calculations. These studies have been carried out on Y/sub 2/Fe/sub 17/ compound, a prototype R/sub 2/Fe/sub 17 /system. Calculations show that the nitrogenation of R/sub 2/Fe/sub 17/ compounds produces the following changes in their magnetic properties: the magnetic moments of the Fe atoms in the vicinity of N atoms decrease, due to their overlap with the N atoms; and the magnetic moments of the Fe atoms away from N atoms increase due to the decrease in their overlap caused by the lattice expansion. This effect increases the interatomic exchange interactions among these atoms, thereby almost doubling the Curie temperature, and there is an overall increase in the total magnetization upon nitrogenation.>