Effect of N₂ Addition on Nanostructure and Magnetic Properties of Sputtered FePt-BN Granular Films During Deposition for Heat Assisted Magnetic Recording

Magnetic properties and nanostructure of FePt-TiN granular films deposited with N2 gas addition for heat assisted magnetic recording media

“…At N 2 gas flow ratio of around 3%, M s film , K u⊥ , and H k, reaches the maximum values of around 630 emu cm −3 , 1.2 × 10 7 erg cm −3 , and 39 kOe, respectively. Similar to the magnetic properties of previously reported FePt-BN granular films, 26) the maximum M s film , K u⊥ , and H k values of FePt-TiN granular films are still lower compared to those of granular films with complete separation.…”

“…For further increase of the N 2 gas flow ratio to 5%, H c maintains a constant value. In the case of previously reported FePt-BN granular films, 26) the maximum H c is observed at 2% N 2 gas addition. This suggests FePt-TiN granular films have wider control range of N 2 gas addition to obtain maximum H c than that of FePt-BN granular films.…”

“…At the Bragg angle of around 24°, the (001) diffraction of the L1 0 -FePt phase is observed which indicates the existence of some magnetic grains with c-axis parallel to the film plane. 32) Interestingly, in contrast to FePt-BN granular films where integral intensity of (001) diffraction increases with N 2 gas addition, 26) FePt-TiN granular films shows no significant change with N 2 gas addition until 5%, which reveals that the (100)-sheet texture FePt grains and variant growth FePt grains are not formed even though N 2 gas flow ratio until 5% is added.…”

“…Similar effect is also confirmed in FePt-BN granular films. 26) Figure 5 shows in-plane XRD profiles for FePt-TiN granular films deposited with various N 2 gas flow ratios. At Bragg angles of around 33°, 47°, and 69°, the (110), (200), and (220) diffractions of the L1 0 -FePt phase are observed, respectively, which reveals that the FePt magnetic grains have c-plane sheet texture.…”

“…24,25) Previously, we have reported that the addition of an appropriate amount of nitrogen gas during deposition of FePt-BN granular films is effective to nitridize B dissolved in FePt magnetic grains. 26) Taking into account that the nitridization effect depends on the metal element of the GBMs, in this paper we focus on TiN GBM. Here the investigation on magnetic properties and nanostructure of FePt-TiN granular film deposited with nitrogen gas addition was carried out in comparison to the previously reported FePt-BN granular film.…”