MAGNETISM OF ALPHA''-FE16N2 (INVITED)

The metastable α]-Fe16N2 phase may have a magnetic moment up to 50% higher than that of pure bulk α-Fe. This article addresses the following issues. (i) Can epitaxial films of α]-Fe 16N2 be prepared phase pure? Yes, but there are some doubts. (ii) Can powders of α]-Fe16N2 be prepared phase pure? Not yet. (iii) Is the Mössbauer spectrum due to α]-Fe16N2, to martensite, or to something else? Most assign it to α]-Fe16N2. (iv) What is the specific saturation magnetic moment of α]-Fe16N2? Some claim it is close to that of α-Fe, most claim that it is much larger. (v) Is the high moment due to α]-Fe16N2, or to some other phase?