Actually it's useful for everyone that I won't start working straightaway, since there's a removal from the old building to a just built one. Therefore I'll carry the most stylish packing cases I've met so far (blue, big plastic boxes labelled with "ANL" or the like).
Nevertheless during a small tour I saw the ALTEM, the AFM, a clear room (including the FIB) and a lot of space to work. To unveil these mystic abbreviations let's look at the following straightforward descriptions (haha, the last senctence is equal to: me, trying to comprehend and summarize wikipedia and my knowledge so far).
But to be honest, just skip the following (blue) section, if you aren't too much interested in the technical stuff (I'll try to keep it short...).
The ALTEM:
Officially the aberration-corrected Lorentz transmission electron microscopy . This magnificent name holds its promises: I was able to make out the shapes of the magnetic blocks in a sample pointing in the same direction! And this sample was just 2μm long. The resolution goes down to 100nm and even smaller, as far as I got it.
Of course (as you might have guessed) the ALTEM is similar to the TEM: the TEM hunts a beam of electrons through a thin sample and detects those electrons afterwards. But these are not that stoic, so they interact with the sample and you can reconstruct the sample's structure by the transmitted electrons.
So, what's so special that the microscope gains two letters? Imagine you start investigating in magnetic structures and you shoot electrons at your sample - of course there will be the Lorentz-force acting on the eletrons and you'll probably see a kind of funny results. The ALTEM outsmarts this effect, but unfortunately I have not found out yet, how this works.
The AFM
A little bit shorter: the atomic force microscope. There's a really tiny needle led across the sample and reacting to the forces between the atoms/molecules and the needle's top (e. g. van-der-Waals-forces, electromagnetic or static ones). With different modes you can deduce the sample's structure on nanoscale as well.
The FIB
(Tatata, the shortest) The focussed ion beam. Instead of hunting a beam of electrons on a surface we use gallium ions which are shot with a low or a high starting current. Thus, possessing a small or a great amount of energy the ions are just reflected (with some interesting side effects, of course) or remove some of the sample's atoms. Therefore I will work on the FIB to change the shape of permalloy samples (to find out what permalloy is you have to read on ;-)).
If you feel the urging wish to collect your ions (and some ufos) again, of course, that's possible. I consider it rather fascinating how the gallium ions are formed: A tungsten needle is wet with liquid gallium and at the top of the needle a cusp shaped tip develops. This happens due to the surface tension keeping the "drop" together and because of the electric field applied. If you look at the tip of the cone you'll measure a diameter of about 2nm. That's so small that the huge electric field causes ionisation of the gallium atoms and their field emission.
A Clean Room!
... is actually not a room equipped with everything you need for a proper spring cleaning as I naively thought. It's of course a room which is extraordinary clean and almost free of dust.
My Activity
1.0 See what others do
Permalloy is fantastic - this nickel-iron magnetic alloy owns a 10 000 times stronger relative permeability than ordinary steel! Now, let's see what happens if you work with the ALTEM on a tiny sample: I was able to identify its Weiss-areas.
What a surprise - these areas depend on the shape of the sample because the Weiss-areas form with respect to the minimum energy and this potential again seems to be influenced by the shape. What might happen if we work on the samples form? - That's our research. And thanks to the focussed ion bombardment the shape's change is made possible.
When I saw the abbreviation I thought of shrimps, but fortunately you spell the program like S-R-I-M, the Stopping and Range of Ions in Matter. The name keeps its promise and I started some simulations from tutorials and some with a Gallium-ion-beam and a permalloy-sample.What a surprise - these areas depend on the shape of the sample because the Weiss-areas form with respect to the minimum energy and this potential again seems to be influenced by the shape. What might happen if we work on the samples form? - That's our research. And thanks to the focussed ion bombardment the shape's change is made possible.
2.0 Get a simulation (SRIM)
... and I continued to read the papers :-) Suddenly, the term "SRIM" appeared and I didn't have to think about another mystical gadget.
Later on we had a meeting with the FIB-supervisor and we found something for me to do: Let's cut out circular shapes and some rectangles (which are more appreciated by the FIB-instrument) and analyse their magnetic behavior with the ALTEM. That's all going to happen once I have been trained on the FIB and the FIB has been fixed...
