As bits get smaller on magnetic hard drives, a different type of sensor must be used to read the narrow tracks of information. The sensing current must be applied perpendicular to the layers in order to minimize the cross talk between written tracks on the disk. The information density is so high that tracks on technology demos now have a width of less than 100 nm and, as such, prototypical devices must mimic the behavior on the nanoscale.
Our program has focused on materials development for these sensors; with recent reports on measurements on sheet films using neutron scattering techniques at national labs [see for example 1]. To test the performance of these materials in nanoscale devices, we have initiated work at the Georgia Tech-NNIN to fabricate nanoscale contacts in GMR devices. The figure shows the optical microscope image of the electrical contacts, and electron microscope images with successively higher magnification of the 6-micrometer diameter insulating pad and the 75-nanometer contact area of the device which will be used for design of materials which exhibit desirable CCP-CPP GMR response.
Figure 1. The CPP spin valve device. The electrical contact pads are shown in the top micrograph, The insulating pad between contacts is shown in the middle and the 75 nm hole in the insulator is shown in the bottom electron microscope image.