What is Piezoelectricity?
Piezoelectricity is a form of electricity created when certain crystals are bent or otherwise deformed. These same crystals can also be made to bend slightly when a small current is run through them, encouraging their use in instruments for which great degrees of mechanical control are necessary. This is called converse piezoelectricity. For example, scanning tunneling microscopes (STMs) use piezoelectric crystals to “scan” the surface of a material and create images of great detail. Piezoelectricity is related to pyroelectricity, in which a current is created by heating or cooling the crystal. The property of piezoelectricity is dictated by both the atoms in the crystal and the particular way in which that crystal was formed. Some of the first substances that were used to demonstrate piezoelectricity are topaz, quartz, tourmaline, and cane sugar. Today, we know of many crystals which are piezoelectric, some of which can even be found in human bone. Certain ceramics and polymers have e
Piezoelectricity, discovered in the 1880’s during experiments on quartz, is produced from the interrelationship of a material’s mechanical and electrical properties. In essence, when a piezoelectric material is squeezed, an electrical charge collects on its surface. Conversely, when a piezoelectric material is subjected to a voltage drop, it mechanically deforms. Many crystalline materials exhibit piezoelectric behavior. A few materials exhibit the phenomenon strongly enough to be used in applications that take advantage of their properties. These include quartz, rochelle salt, lead titanate zirconate ceramics (e.g. PZT-4, PZT-5A, etc.), barium titanate, and polyvinylidene flouride (a polymer film). On a nanoscopic scale, piezoelectricity results from a non-uniform charge distribution within a crystal’s unit cells. When such a crystal is mechanically deformed, the positive and negative charge centers displace by differing amounts. So while the overall crystal remains electrically neutr
