Ferromagnetic and spin wave resonances in thin layer of expanded austenite phase

Abstract

Four samples of austenite coatings deposited by reactive magnetron sputtering on silicon substrate at four different temperatures and pressures were investigated by ferromagnetic resonance (FMR) method at room temperature. The expanded austenite phase S (γ N ) layers with thickness in the 160 -273 nm range and concentration of magnetic atoms: 72 % Fe, 18 % Cr and 10 % Ni, were obtained. The coatings with nanometric size grains were strongly textured and grown mostly in [100] direction, perpendicular to the sample surface. Intense FMR spectra were recorded at various angles between the static magnetic field direction and the sample surface. A strong magnetic anisotropy of the main uniform FMR mode was observed and the effective magnetization 4πM e f f determined. Spin wave resonance (SWR) modes were observed in all investigated samples in out-of-plane geometry of the magnetic field. The resonance fields of SWR modes in our samples varied linearly with the spin wave mode number. The value of the effective magnon stiffness constant was determined assuming a parabolic shape of the magnetization variation across the sample thickness.

Structural, tribological and corrosion properties of plasma nitrided-chromized-316L stainless steel in air and artificial seawater

“…Meanwhile, a metastable nitrogen supersaturated solid solution called expanded austenite (S phase) can be formed in the diffusion layer. The S phase can impart high hardness, wear resistance, and excellent corrosion resistance to the 316L stainless steel [15][16][17][18]. However, the S phase would degrade to produce CrN precipitation from the nitrided layer when carried out the high-temperature nitriding treatment (>500 °C).…”

“…However, the S phase would degrade to produce CrN precipitation from the nitrided layer when carried out the high-temperature nitriding treatment (>500 °C). This can induce the chromium depletion of the matrix, resulting in poor corrosion protection of the nitriding layer [15][16][17]. Thus, low-temperature plasma nitriding (<430 °C) attracts more attention for 316L stainless steels to maintain the performances of the S phase.…”