The best experiment I’ve done is probably when I went to the Netherlands to use some of the most powerful magnets in the world! I study electron spin and one way to investigate this is to use magnetic fields and electrical current to observe quantum effects because spin interacts with magnetism (in fact, it can be thought of as electrons being tiny bar magnets in a way). We worked with these amazing magnets with some awesome people and our results were really interesting and not quite what we expected which made it even more exciting!
Here’s a photo of one of the magnets I got to work with (the big tank is liquid nitrogen and the magnet is actually underneath the floor in this lab! My device was put in one of those long sticks and lowered under the floor into the magnetic field):
In terms of creations, this prototype device is the closest I’ve come to making something that can polarize spin at low temperatures (which basically means forcing electrons with each spin state into different directions in a material):
This image was taken using something called a scanning electron microscope which allows us to see things at a much smaller scale than an optical microscope like the ones you might have used at school. It basically shoots a beam of electrons at the surface you’re taking a picture of and then detects the electrons that have been scattered by the surface which lets us build up the image!
The scale bar there is 100um which is around the thickness of a human hair so those channels that I’ve dug out are incredibly tiny (a few 10s of nm wide)! Those blobs are where I attach incredibly thin gold wires to the device so that I can pass electricity through the device and measure things like voltages and current across different ‘arms’.
I’m still in the process of measuring this device and investigating what the electrons are doing quantum mechanically but it was nice clean work that I did with my etching (cutting out the pattern that you can see across the centre of the device).