Magnetic properties and structure in Co-based nitride thin films

Experimental results on the magnetic properties and structure in Co-based nitride thin films are presented. The high-temperature stability of magnetic softness in Co-based nitride films is shown to originate from crystalline structure with very small dimension, confirmed by small-angle X-ray diffraction and Mossbauer spectroscopy, though only halos are observed in a normal X-ray diffraction experiment. By structure transformation from amorphous to small crystallite magnetostriction changes rapidly and magnetic moment increases. These structures influence magnetic anisotropy induced by field cooling. The anisotropy cannot be controlled below 500°C in the CoZrN films, though by addition of Fe the anisotropy can be controlled up to 350°C. It is suggested that this anisotropy originates from hexagonal-close-packed-like atomic stacking order in the FCC Co crystallite