Magnetic properties of ε-Fe₃N–GaN core–shell nanowires

epsilon-Fe(3)N-GaN core-shell nanowires are synthesized by the wet chemical route and by nitridation of the Fe-Ga-oxide nanowires in flowing NH(3) (g). The encapsulation by the GaN shell protects the epsilon-Fe(3)N core and spin-glass-like cooperative ordering is observed at low temperatures. Magnetic disorder occurs at the epsilon-Fe(3)N-GaN interface, giving rise to the spin-glass-like state below 50 K because of the presence of anti-ferromagnetic (AF) mixed oxynitrides and ferromagnetic (FM) epsilon-Fe(3)N nitride and the random distribution of epsilon-Fe(3)N in the interface region. The spin-glass-like ordering is probed by relaxation and ac susceptibility experiments.