Magnetic anisotropy and permeability in sputtered iron aluminum nitride thin-film materials

Significant improvement in magnetic properties of FeXN (X = Al, Zr, Ta…) thin films deposited on the sloping surfaces, especially at 60°, was achieved by using various interlayer materials or proper sputtering conditions. The oblique incidence problems in permalloy and CoZrRe thin films were also greatly improved. Test heads fabricated using these materials showed improved permeability.; Significant improvement of the thermal stability in FeXN thin films was also achieved. Sputtered at the reduced target-substrate spacing of 38 mm, 200 nm thick thermally stable FeXN thin films were obtained. They had hard axis coercivity ≈0.1–2.0 Oe, easy axis coercivity ≈1.5–3.0 Oe, H_k = 8–16 Oe and B_s = 19–20 kG. Results from transverse field annealing experiments in a uniform field of 700 Oe show no significant change of magnetic properties at 150°C for 3 hours. At 150°C for 24 hours, H_k decreased by 2–4 Oe. Their easy/hard axes did not rotate and the coercivity remained almost unchanged. This superior thermal stability of FeXN films is promising for high moment write heads.; The effects of N doping on the magnetic and structural properties of a series of 100 nm FeAlN films sputtered in the presence of N partial pressures were investigated. Increasing N doping increased film resistivity but decreased MS. Extended x-ray absorption fine structure spectra of the short-range atomic order in the Fe(Al) lattices directly indicated that the N went into octahedral sites of bcc Fe and fcc Fe in α-Fe and γ′-Fe ₄N phases, respectively, and triggered the order-disorder phase transition observed in x-ray 0–20 diffraction spectra. Mild N doping decreased the grain size and reduced H_c. It also increased the local atomic disorder, which coincided with the maximal value of K_u and the in-plane anisotropic behaviors in the as-deposited films. The roles of N doping in FeXN film optimization processes and its effects on magnetic and structural properties, especially the uniaxial anisotropy and its thermal stability, were investigated. The locations/distributions of N incorporation in the films are being investigated and compared with the film properties.