High coercivity CoCrPt-SiO₂granular thin films for magnetic recording

Abstract

Granular CoCrPt-SiO2 thin films with Cr underlayers have been fabricated by sputtering followed by post-deposition annealing. Microstructural and magnetic properties of as-deposited and annealed films have been investigated for potential applications in magnetic recording media. The grain size of about 10 nm was obtained in the as-deposited films, and subsequent annealing did not lead to significant grain growth. High coercivity up to 5640 Oe was achieved upon annealing. The Mrt value can be down to about 0.4 memu cm-2 for films with Hc exceeding 5000 Oe. The peak value of the delta M curves changed from a positive value in as-deposited films to a negative value for annealed films, indicating an obvious reduction of intergrain magnetic exchange coupling after annealing.

Effects of thermal annealing on structural and magnetic properties of thin Pt/Cr/Co multilayers

“…However, since the mixing is not adequate, no signature of any mixed phase is detected in the corresponding XRD pattern. At the higher annealing temperatures of 773 and 873 K, the Pt and Co signals completely disappear and a new peak corresponding to the CoCrPt (0 0 0 2) reflection appears at 2y ¼42.51 [13][14][15][16]. Thus, it seems that at 873 K, complete mixing takes place amongst the constituent layers of Pt/Cr/Co ML structures, which is in good agreement with our XRR results discussed earlier.…”

Thermal stability of L10-FePt nanodots patterned by self-assembled block copolymer lithography

“…For example in heat assisted magnetic recording [6,7], local heating of a region of a high anisotropy magnetic recording medium lowers the energy barrier to the point that the field of the write head is capable of writing data on the medium. This enables the use of hard magnetic materials such as CoCrPt, FePt, CoPt, or FePd [5][6][7][8][9][10][11] for recording media which can have coercive fields over μ 0 H c =3 T after patterning, above the maximum field of ∼2.4 T that a write head can apply.…”

L 1 ordering and magnetic interactions in FePt nanoparticles embedded in MgO and SiO2 shell matrices

“…A similar approach has been used to make granular films of FePt/ Al 2 O 3 , 23 FePt/ MgF 2 , 23 CoCrPt/ SiO 2 , 24 and FePt/ MgO. 25,26 MgO can serve as a shell matrix since it hinders the aggregation of the metal particles and can be dissolved from the nanocomposite using low concentration acid solutions ͑e.g., HCl͒, leaving the structural characteristics of the magnetic nanoparticles almost intact.…”