Mössbauer study on Fe16N2 films prepared by ion-implant nitrification of iron films

Abstract

Mössbauer spectroscopy was carried out to elucidate the magnetic structure of Fe₁₆N₂ with the giant magnetization. Samples were prepared by ion‐implant nitrification of single‐crystal iron films, followed by an annealing at 150 °C for 60 h. The nitrification developed three Fe atom environments, attributable to three different Fe sites in Fe₁₆N₂ structure. The magnetic moments of the first, second, and third nitrogen neighbor Fe atoms were determined to be 1.3, 2.5, and 3.8 μ_B, respectively. The quadrupole effect in Fe₁₆N₂ was interpreted consistently on the basis of the consideration that the magnetization is directed along [001] and nitrogen atoms had a negative charge.