Magnetooptical thin film optical constants measurement using surface plasmon resonances

Rare-earth-transition-metal thin films are extensively studied as materials for erasable magnetooptical (MO) data storage media. MO Kerr effects can be enhanced by interference effects using multilayer designs. The optical constants n and k are required for the design of multilayer structures, but little data exist for MO materials. We have developed a method to measure the constants using the surface plasmon resonance phenomenon. We measured the constants of TbFe films deposited by rf sputtering. The accuracy estimation was about +/-0.005 and could be as good as +/-0.001 for optimum conditions.