Tiny Tech #16: Superparamagnetic Nanoparticles

Today from the world of Tiny Tech:

The dark “mag-stripe” on your credit card is made of iron-containing particles, each of which is a magnet with a north and south pole.  The information on your card is stored by making magnetic patterns, in which the poles of the particles point in different directions from place to place on the stripe.  Once made, the patterns stay in place for a long time.

In theory, more information could be stored on a credit card if the magnetic particles were smaller.  But there is a problem:  if the particles are too small, they rapidly change their north and south pole directions.  Such nanoparticles are called superparamagnetic.  A credit card made with these particles wouldn’t be very useful, because the stored information would erase itself in a few seconds.  However, scientists have discovered recently that superparamagnetic nanoparticles have just the right properties for certain uses in medicine.  For example, when injected into the body they can increase the contrast of MRI images, and they help ensure that injected drugs reach their intended target.

So, sometimes being small is a super thing to be!

Tiny Tech is made possible by the National Science Foundation and WUFT.  To learn more about Tiny Tech, go to tinytechradio.org.

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