Growth, structure, and magnetic properties of γ′-Fe4Nγ′-Fe4N thin films

We have grown phase-pure, buffer-free, and epitaxial α -Fe and γ′-Fe4Nγ′-Fe4N thin films by RF magnetron sputtering onto MgO (100) substrates. The film thicknesses and densities have been determined with high accuracy by evaluating the Kiessig fringes of the X-ray reflectometry measurements. We have determined the volume saturation magnetization of γ′-Fe4Nγ′-Fe4N with corresponding accuracy to be View the MathML sourceMs=1556±62emu/cm3 at 10 K or View the MathML source2.30±0.09μB per Fe atom. The Curie-temperature, TCTC, of the γ′-Fe4Nγ′-Fe4N thin films was 716 K. The slightly increased average magnetic moment per Fe atom of γ′-Fe4Nγ′-Fe4N as compared to α-Fe is in agreement with literature values and attributed to the volume expansion of the unit cell