Glass composite including dispersed rare earth iron garnet nanoparticles

DETAILED DESCRIPTION The present invention overcomes the problems outlined above and provides new glass/nanoparticle composites and methods of fabrication thereof, allowing controlled production of very high nanoparticle density composites.
Broadly speaking, the composites of the invention include a body of glass having embedded therein a plurality of heterologous nanoparticles, with at least certain of the nanoparticles having a diameter of up to about 500 nm.
Preferably, the nanoparticles are characterized by the property of altering the polarization of incident electromagnetic radiation which is reflected or scattered from the nanoparticles.
The most preferred type of nanoparticles are the rare earth iron garnet nanocrystals, especially yttrium-iron nanoparticles.
Here, the term "nanoparticle" is defined as a particle, the size of which is between several nanometers and several hundred nanometers.
The term "nanocrystal" is defined as a crystal grain the size of which is between a several nanometers and several hundred nanometers.
In forming the composites, a porous glass body such as "thirsty glass" is contacted with a dispersion including the heterologous nanoparticles, so that such nanoparticles locate within the surface pores of the glass body.
Thereafter, the nanoparticle-treated glass body is heated to fuse the pores and embed the nanoparticles.
Most preferably, the nanoparticles are initially in an amorphous state, and the heating step serves to transform these nanoparticles into a crystalline state.
These methods produce stable composites which can be used as a part of electrooptical recording media.
Nanoparticle loadings on the order of 10.
sup.
9 nanoparticle/mm.
sup.
2 of glass surface area are possible.
This allows construction of recording media having a recordable data density many times greater than conventional media.