| This dissertation presents development of low noise soft magnetic underlayers for perpendicular magnetic recording media. Soft underlayers can give rise to additional media noise primarily due to domain wall instabilities. Ferromagnetic/antiferromagnetic exchange-coupled multilayers provide a unique solution to several problems found with uniaxial soft underlayers. Initially, FeTaN/IrMn multilayers with a single domain remanent direction demonstrated the reduction in noise but showed 19 total layers including IrMn and thermal instability. These were overcome by using FeCo alloys. This work focused on achieving soft anisotropic high magnetization FeCo films and in understanding the origin of their soft properties. These results were used to produce radially oriented thermally stable high moment FeCo/IrMn soft underlayers. |
