The present invention relates to an information storage medium and a method for long-term storage of information comprising the steps of: providing a ceramic substrate; coating the ceramic substrate with a layer of a second material different from the material of the ceramic substrate, the layer having a thickness no greater than 10 m; tempering the coated ceramic substrate to form a writable plate or disc; encoding information on the writable plate or disc by using a laser and/or a focused particle beam to manipulate localized areas of the writable plate or disc.

The invention refers to an ultrafast quench based nonvolatile bistable device which consists of an active material on a passive or active substrate which changes its physical properties, after exposure to a sufficiently temporally short external perturbation causing an ultrafast quench. The perturbation can be from an external ultrashort laser pulse or ultrafast electrical pulse from an electrooptic device or any other generator of ultrashort pulses. This change of the materials properties can be detected as a change of optical properties or electrical resistance. The dielectric properties can be reverted back to their original state by the application of a heat pulse applied by an electrical heater within the device or an external laser.

An optical recording medium includes a plurality of information signal layers on which information signals are to be optically recorded. Among the plurality of information signal layers, the information signal layer closest to the light-receiving surface has a reflectance of more than 4%.

Provided is a MnTaWCuO-based sputtering target including, in the component composition, Mn, Ta, W, Cu, and O. The sputtering target has a relative density of at least 90%, and includes a crystal phase of Mn.sub.4Ta.sub.2O.sub.9. Also provided is a production method for the sputtering target.