Pseudo-hcp nonmagnetic intermediate layer for granular media with high perpendicular magnetic anisotropy

Abstract

Materials with the hexagonal close-packed structure (hcp) and the face-centred-cubic structure with stacking faults (pseudo-hcp) are examined for the nonmagnetic intermediate layer (NMIL) in order to suppress variant growth of magnetic grains for granular-type perpendicular recording media. Judging from the analysis of the epitaxial growth of Co-based magnetic grains, it has been found that a lattice misfit between NMIL and magnetic grain of less than 6% and a spreading coefficient of wettability of magnetic grain on NMIL of greater than 0.3 J m−3 are required for the recording layer to have high perpendicular magnetic anisotropy energy.

Advanced granular-type perpendicular recording media

“…), addition of the bcc metal former (Cr, Mo, W, Ti, Nb, etc.) into the host fcc material is quite effective [3,4]. Fig.…”

“…Based on these discussions, we propose new fcc materials with highly coherent SFs as alternative NMIL materials to replace hcp Ru, focusing on the conditions required for epitaxial growth [4]. …”

Tailor-made nano-structured materials for perpendicular recording media and head—precise control of direct/indirect exchange coupling

“…This anomalous sputtering process condition leads to some chemical instability (low density of the film) and increased roughness on the top surface of the disk [44]. Therefore, in order to further improve these granular media for high density recording, several key technical issues need to be established, including (1) self-organized nano-dot array formation as a template for the recording layer by a sputtering process, (2) nano-granular thin film formation (recording layer) onto nano-dot arrays used as templates, and (3) development of alternative materials to Ru from the view point of mineral resources [45][46][47].…”

Extreme Nano-structure Control by Sputtering for the High Density Perpendicular Recording Media and Head

“…), addition of the bcc metal former (Cr, Mo, W, Ti, Nb, etc.) into the host fcc material is quite effective [12][13]. Figure 6 shows Technical issue on development of pseudo-hcp materials was experimental evaluation of the degree of stacking order quantitatively.…”