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

• Phase-pure and epitaxial γ′-Fe4Nγ′-Fe4N thin films were grown onto MgO (100) substrates.
• Thickness of the γ′-Fe4Nγ′-Fe4N film was determined by X-ray reflectometry.
• Structure, elemental composition, electronic, and magnetic properties were studied.
• The magnetic moment per Fe atom in γ′-Fe4Nγ′-Fe4N was 2.30±0.09μB at 10 K.
• Curie-temperature of the γ′-Fe4Nγ′-Fe4N is estimated to be approximately 716 K.

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 Ms=1556±62emu/cm3 at 10 K or 2.30±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.