My group’s goal is the integration of photonic and magnetic materials and devices onto convenient platforms. Currently, we are focusing on 1) magnetic nanowires arrays for artificial cilia and magnetic random access memory (MRAM) and 2) magneto-optical waveguides and photonic crystals.

First, we use nanowires to mimic cilia (tiny hair-like sensors) that play a very important role in detection for many biological species, including humans. Magnetostrictive nanowires are used for acoustic sensors with high-spatial resolution and high sensitivity. Because the dimensions can be tailored from 10-300nm diameters and 10-10,000 nm lengths, these nanowires can be used over a wide range of frequencies for detecting sonar, ultrasound, hearing, fluid flow, and/or chemical contamination. For MRAM, nanowires composed of giant magnetoresistive (GMR) Co/Cu layers with alternating hard and soft Co are grown. There is a clear advantage to nanowire MRAM because the arrays inherently possess high areal densities.

In photonics, we are equipping integrated optical circuits with important devices that are currently available only as discrete components, such as isolators. The major roadblock to integrated isolators is the difficulty of incorporating magneto-optical garnets onto non-garnet substrates. The complex structure of garnet requires high energies to form, but many substrates (eg: semiconductors) cannot tolerate excessive annealing. We have used reactive RF sputtering and rapid thermal annealing which allows the formation of garnet without damaging substrates. Currently, various types of devices, including ridge waveguide devices and photonic crystals, are being fabricated using photolithography, nanostructured etch masks, and focused ion beam.