Breakfast of Galfenol Champions

Also called Magnetostrictive Nom Noms.

This summer I've been working in a lab on campus doing research with magnetostrictive materials - mainly, one called galfenol. A magnetostrictive material is one that changes shape when subjected to a magnetic field, or which produces a different magnetic field when its shape is changed. The applications for this type of material are endless, and my job for this summer has been to characterize galfenol's (an iron gallium alloy) magnetostrictive properties in terms of sensing and actuation so a model can be developed.

Annnnyway, the annual MURI review (a conference where engineers and scientists give seminars on their work with galfenol and other magnetostriction projects) has been taking place yesterday and today, and it's allowed me to listen to some particularly exciting seminars. And I also get free food. The combination of both is called a WIN. See below.


I'm sure this sounds awfully exciting to all of you, but it's actually incredibly interesting. One aspect of particular interest at this conference has been the utilization of galfenol nanowires. To visualize, imagine the diameter of a human hair. Now imagine about 90,000 tiny, tiny wires packed within that diameter. And imagine that each of those wires produce a magnetic field in a certain direction. Now, say either acoustic waves or a slight breeze pass along those wires. What happens? Well, they're not terribly stiff, so they bend. And suddenly the magnetic field direction changes. And tiny sensors (actually called "giant magnetoresistive sensors") can pick up this change in field. Suddenly, you have the opportunity to sense small changes in air flow or acoustic flow.

Looking for an example of this that already exists? Well, look no further than your ear. Tiny hairs in your ear, called cilia, vibrate at some resonant frequency and send electrical signals to your brain, which is processed as sound.

Interesting stuff, magnetostriction.


Also, LA Countdown: 11 days.