It’s been a while since my last blog post and I naturally have progress on my project! It’s exciting to have my system ready to go and I’ve started to get a few results through. Nothing concrete yet but it’s behaving a bit like I was expecting! I’m going to spend a bit of time here explaining how I carry out my research.
So here’s where it gets a bit science-y. In my last post I said I was investigating magnetic nanopatterns. You’re probably familiar with magnets like the bar magnets in school…
At the scale of a bar magnet, you can see magnetic field lines by scattering iron (a ferromagnetic material) filings nearby. There are a set of rules that mean a bar magnet, or indeed any magnetic material, behaves like this, and these depend on some energy terms that I won’t delve deeply into. Energy likes to be minimised for things to exist in stable states but the usual ways a magnet reduces its energy happen over distances greater than the sizes of the magnets I’m investigating! Therefore at the nanoscale, it becomes a lot harder for materials to follow the rules which leads to the strange behaviour.
So to look at magnets on the nanoscale we need to grow them first. My structures are grown by using electron beam lithography (EBL) followed by deposition of NiFe and then removal of a polymer photoresist. Imagine you are spray painting a pattern on a wall. You might use masking tape to cover the bits you don’t want to paint, spray all over and then remove the masking tape to leave an unpainted region. It’s kind of like that except you use masking tape, in this case an electron beam ‘writing’ a pattern on a polymer surface, where you do want material to end up. Once you have ‘sprayed’ NiFe onto the whole surface, you remove the polymer and all you are left with is the NiFe that deposited in the gaps formed by EBL.
After that it’s over to the optical bench where lasers are fired at the sample. This sounds a lot cooler than it actually is – if only materials research was a bit more like Star Wars… When light is reflected from a magnetic material in a magnetic field it changes a bit. These changes can be detected using polarisers (a bit like your sunglasses) and are used to characterise the magnetic material and observe some of the strange behaviour talked about earlier.
That’s the basics of what I do. PhD life is not all about the research though. One thing I’ve been involved in recently is facilitating the project weeks that first and second year engineering undergraduates do. In these, teams of multidisciplinary engineers have to come up with a solution to a real world engineering problem such as coming up with a sustainable water supply for a small town in a third world country. These project weeks are a huge advantage to engineering courses at the University of Sheffield.
I remember when I interviewed for my placement I had so many examples of team working, time management, organisation, communication that employers look for when recruiting that came from these weeks.
Feedback from employers is always overwhelmingly positive for the experiences that undergraduates gain from these weeks, and those that come in to help run some of the sessions were very impressed by the quality of some of the solutions on offer!
That’s all for now, in my next post I’ll go into one of my favourite aspects of my time as an undergraduate (other than Pop Tarts, the SU retro night) – the placement!
PhD student, SCAMMD