Researchers from Germany's Max Planck Institute of Microstructure Physics have reported a lift-off and transfer method to fabricate three-dimensional racetrack memories from freestanding magnetic heterostructures grown on a water-soluble sacrificial release layer.
The fabrication of three-dimensional nanostructures is key to the development of next-generation nanoelectronic devices with a low device footprint. Magnetic racetrack memories encode data in a series of magnetic domain walls that are moved by current pulses along magnetic nanowires. To date, most studies have focused on two-dimensional racetracks.
The team started by creating two-dimensional racetracks from freestanding films transferred onto sapphire substrates and show that they have nearly identical characteristics compared with the films before transfer. Then, the researchers designed three-dimensional racetracks by covering protrusions patterned on a sapphire wafer with freestanding magnetic heterostructures.
They demonstrated current-induced domain-wall motion for synthetic antiferromagnetic three-dimensional racetracks with protrusions of up to 900 nm in height. Freestanding magnetic layers may enable future spintronic devices with high packing density and low energy consumption.