Performance study of ferromagnetism for optical media

• Main Author: Toh, Kah Long.
• Other Authors: Gan Chee Lip
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/15139
• Institution: Nanyang Technological University

Magneto-optical recording requires optical discs that show relative square hysteresis loop and have coercivity greater than 1000 Oe. TbFeCo, a Rare Earth Transition Metal best fits the requirements for magneto-optical media. The disc for this project is made up of four layers deposited on a polycarbonate substrate. A metallic reflector layer was deposited as the first layer, a dielectric layer was deposited as the second layer while the magnetic layer, TbFeCo was deposited as the third layer and lastly, the magnetic layer was capped with another dielectric layer as the fourth layer to prevent oxidation. The effects of different methods of sputtering, different thickness of the magnetic layer, different sputtering power and the interchange of Al-Cr and AgPdCu as reflective layer were investigated. It was found that coercivity value will increase with increased temperature, increasing thickness of the magnetic layer and sputtering power while changing Al-Cr and AgPdCu as the reflective layer yields almost the same values.