Producing Three Dimensional Nanostructured Magnetic Materials for Novel Magnetic Devices

Abstract

Abstract : We have produced large sized 3D magnetic nanocomposites using a current activated pressure assisted densification (CAPAD). We were successful in producing dense nanocrystalline ( 100 nm average grain size) materials based on iron oxides (ferrites), rare earth oxides and silicon We have demonstrated magnetic coupling leading to exchange bias in large nanocrystalline iron oxides. Additionally we can orient the magnetically coupled grains causing their magnetic properties to be highly anisotropic. These materials have promising applications in magnetoresistance based devices as well as permanent magnets. The rare earth oxides are transparent to visible light and cause very high Faraday rotations. The Verdet constant of these nanocrystalline materials is more than twice that of the state of the art Faraday rotation materials. We also used the CAPAD technique to show that the thermal conductivity in of polycrystalline silicon can be controlled using nanostructure.