PRESENT AND FUTURE OF MAGNETOOPTICAL RECORDING MATERIALS AND TECHNOLOGY

Erasable optical information storage from amorphous rare earth-transit ion metal (RE-TM) alloys media has led to impressive improvements towa rds hyper high density recording in the past five years. Write/erase a nd readout processes are based on light-induced thermomagnetic switchi ng of magnetic domains and magnetooptical (MO) Kerr effect, respective ly, in ferrimagnetic films exhibiting a uniaxial magnetic anisotropy. The route towards ultrahigh optical areal densities was open from the beginning of the nineties from two key technologies related to near fi eld optical techniques and RE-TM exchange-coupled bi, tri- and multila yers. The performances of the MO media depend on the types and states of these multilayers with perpendicular or mixed (perpendicular and pl anar) anisotropies which change with the temperature and the applied f ield. The development of the thermomagnetooptical materials is discuss ed with reference to their magnetic and MO properties to increase the density storage. (C) 1998 Elsevier Science S.A.