At just 11 atoms the world’s smallest sensor sheds light on the quantum realm

Everything is getting smaller. Like this single atom transistor, or this transistor that, literally, has no size at all. Or this camera that is so small it can travel through your blood stream scanning you from the inside out. Or this computer that’s the size of a bacteria – because it is a bacteria. And so on. And sensors are by no means immune from being miniaturised either after researchers at Delft University of Technology announced they’ve developed one of the world’s smallest sensors at just 11 atoms in size.

The sensor is capable of capturing magnetic waves and consists of an antenna, a readout capability, a reset button and a memory unit. The researchers hope to use their atomic sensor to learn more about the behaviour of magnetic waves, so that hopefully such waves can one day be used in green ICT applications.

In theory, engineers can make electronic data processing much more efficient by switching to spintronics. Instead of using electrical signals, this technology makes use of magnetic signals to transmit data.

Courtesy: Delft University

Unfortunately, magnetism tends to get incredibly complicated, especially at the tiny scale of computer chips. A magnetic wave can be viewed as millions of compass needles performing a complex collective dance. Not only do the waves propagate extremely quickly, causing them to vanish in mere nanoseconds, the tricky laws of quantum mechanics also allow them to travel in multiple directions at the same time. This makes them even more elusive. So the team made their new minuscule sensors in order to study these rapid oscillations.

The sensor’s equipped with an antenna, a readout capability, a reset button and a memory unit to store the measurement outcomes. The central idea of the invention is that the device instantly detects a passing magnetic wave and remembers this information.

"Compare it to a mouse trap," research leader Sander Otte explains. "A mouse is typically too fast and too small to capture by hand. But a mouse trap reacts very quickly and then hold the mouse in place."

The researchers connected the device to magnetic atomic wires through which magnetic waves were transmitting. Although the test wires were very short, the results are promising: The waves moved very peculiarly, as one would expect from quantum mechanics.

Now, the next step is to apply this technique to more complicated circuits in order to gain more insight into the behaviour of spintronics.