Magnetic and electrical properties of (Er<inf>1−x</inf>Pr<inf>x</inf>)<inf>2</inf>Fe<inf>17</inf>N<inf>y</inf>

A nitrogenation facility working in the pressure range 0–100 bar and temperature range 30–600°C was fabricated and the nitrides were prepared. There is an increase in the unit cell volume by about 8% for a nitrogen concentration of 2.7. Similarly there is an increase in the magnetization as well as the Curie temperature after nitrogenation for all the compounds. The increase in the magnetization is due to the increase in the average Fe moment as a result of lattice expansion following nitrogenation. The increase in the Curie temperature is explained on the basis of spin fluctuation theory. A tentative spin phase diagram is proposed based on the magnetization and ac magnetic susceptibility measurements. Upon nitrogenation, the resistivity of the samples increases by one order of magnitude still retaining the metallic behaviour. © 1995 IEEE