Shorthand for “micro-electromechanical machines,” MEMS are the tiny machines embedded in these products, which provide information regarding position and movement. When your mobile device changes how its screen displays when you rotate it, it is an MEMS device that tells it which way it is oriented. Like most of the electronic innards of a modern computer, MEMS are usually manufactured out of silicon.
With funding from the National Science Foundation, University of Wisconsin-Madison researchers have advanced MEMS technology by integrating new piezoelectric materials on silicon. Piezoelectric materials store an electrical charge when under mechanical force, or expand and contract under the influence of electrical fields. If you’ve used a lighter or propane barbecue that has an electrical igniter, you have seen piezoelectricity at work. Children’s shoes that light up when they step also use piezoelectricity to generate a small electrical current.
The University of Wisconsin-Madison researchers studied a piezoelectric material called lead magnesium niobate-lead titanate, or PMN-PT for short. PMN-PT is a very high-performance piezoelectric crystal that is used, among other things, to deliver waves of ultrasound into the human body to produce 3-D images.