All-metal current perpendicular to the plane (CPP) giant magnetoresistance (GMR) layers have been made within insulating matrices by direct growth to avoid sidewall damage that is caused by lithographical patterning in current vacuum-deposited devices. These insulating matrices can be made to have nanostructures with multiscale order to allow photolithographical alignment of contacts to 10-500 nm devices. This alignment was demonstrated with 100-200 nm diameter structures to prove feasibility. Next, trilayers of [Co(15 nm)/Cu(5 nm)/Co(10 nm)] with 10 nm diameters were made by electrochemical deposition with 30 Ω resistance and 19% magnetoresistance. These parameters are desirable for read head sensors, especially because the nanowires described here have 1:1 aspect ratios, 10× smaller areas, and 100× lower resistances than conventional read sensors based on lithographically-produced magnetic tunnel junctions. Finally, the potential application of closely spaced arrays of CPP GMR sensors for enabling one-pass two dimensional recording as well as a new technique called cross recording will be discussed.
Bibliographical noteFunding Information:
This work was supported by NSF GOALI (ECS-0621868) and MRSEC (DMR-0212302 and DMR-0819885), and UMN Nanofabrication Center and Characterization Facility via the NSF NNIN program.
- 2-D recording
- CPP GMR
- cross recording
- read sensor arrays