# crystallography

## Back from the ECM-30 meeting in Basel

During this week, I was in Basel to participate in the 30th meeting of the European Crystallographic Association (ECM) – the first time for me to participate in this conference. There were way more people than I had expected – I heard mentioned around 920 participants – and the whole thing was super inspiring.

I had actually tried getting a talk about my almost-ready to publish work on staging in LSCO, but I only got to present a poster. I did, however, get to catch up with a few people, as well as meet some of the people that I met at the Aperiodic Crystals school back a few weeks ago in Antwerp.

Monday evening there was a Young Crystallographers Mixer at the Bar Rouge in the second-highest building in Basel. The view was amazing, the drinks were great, and the music was loud. Quite a fun experience, although I’m not sure whether it worked well for networking or not..

Tuesday evening I got to visit the new Dectris headquarters in Baden-Daettwil, with a really interesting tour, as well as some awesome barbecue to top it off afterwards. It was really cool to see where they make the Pilatus detectors that I’ve seen so many times, as well as hear about all of the newer products they have been developing, and the history of the company.

The venue itself was really great, and there was a professional team of conference arrangers that took care of the practicals – everything ran so smoothly! We also had some pretty long lunch breaks, so there was good opportunity to get around Basel a bit. I might actually go to Basel again on a vacation some day, it was a great city – and the public transport was very efficient.

Finally, the conference dinner on Wednesday evening was held in the Zoo in Basel, in one of the big restaurant halls. Before the actual dinner (which was awesome, by the way), we were divided into groups and sent on tours around the Zoo. I got on the tour in their little aquarium, where one of the biologists showed us around in the back, where they breed corals, seahorses, and jellyfish. It was super interesting, and way too short. I could have stayed there for hours and hours.

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## Aperiodic Crystals school in Antwerp

This last week I participated in the Aperiodic Crystals school held at the University of Antwerp in Belgium. It was a week of lectures and tutorials on modulated crystal structures and quasicrystals, and was basically perfectly catered for what I need for my continued PhD project.

Apart from learning a bunch of useful knowledge about superspace and superstructures, I also got some more knowledge about how to use JANA2006 to solve (in)commensurately modulated structures from single crystal data. Now I just have to figure out how to index the data that I already have…

The week ended up being super busy for me, but there was some time in the evenings to go out with people, finding interesting local beer and food. I was especially happy about finally trying cherry beer (kriek), which I’d never even heard of before. I also got to meet a lot of new awesome people, both fellow participants of the school and lecturers – some of which I’ll meet again soon at the ECM-30 conference in Basel at the end of August.

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## Article in Physical Review B!

Top part of the published paper

Astrid put together this awesome paper on the work she’s been doing the last years. I helped with a bunch of the experiments back when I’d just started my PhD, so it is great to get it published too!

As a short description, the article is about the field dependence of the interplanar magnetic correlations in our LSCO-O sample. We found that the applied field enhanced the magnetic moments and increased the interplanar correlations (though only between neighboring planes). Also, these interplanar correlations could apparently also be forced through a fast cooling instead of an applied field.

The full article can be found through the DOI number: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.174507

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## Another DMC beam time on LSCO+O, and a little PCMO

From November 21 to 28 we had another beam time at the DMC instrument at SINQ, where we measured reciprocal space maps for two of our LSCO+O crystals.

I arrived a couple of days early to align the samples, and had some very late nights because things didn’t want to work – as is seemingly the usual when aligning crystals… If nothing else, I got to entertain myself with how much the sample holders looked like little robots.

The measurements themselves went perfectly, and we had some extra time to put a powder sample of PCMO on the instrument in the end. Hurray for beautiful data to take home!

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## Structural State of Minerals and its Applications course

PhD course on different software used for X-ray scattering (both powders and single crystals), primarily on minerals – held at the Geocenter at the University of Copenhagen. The course addressed the use of the structural information obtained by modern diffraction methods and computational approaches in mineralogy and materials science and was mainly directed towards PhD students in geosciences and related disciplines. I was hoping to learn more about – in particular – superstructures and how to handle them, since these are found in a lot of mineralogical samples.

We spent a lot of time on basics of crystal structures and diffraction – which was a repeat of what I’ve seen a lot already – but then moved on to looking at behaviour of crystals under varying temperature and pressure, powder diffraction and applications and finally structure interpretation and specific applications in geoscience and material science. We had both lectures and experimental work with an introduction to modern diffractometers using one of the X-ray diffractometers at the department. We also got to test out a range of different crystallographic software in short tutorials.

All in all, I’m not sure if I learned much about superstructures that I didn’t already know, and I definitely did not find the holy grail of how to solve my crystal data – but, if nothing else – it was an interesting course with some new knowledge.

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## Working a couple of weeks at the Rutherford Appleton Laboratory

From April 1st to 13th, I’ve been at the Rutherford Appleton Laboratory (RAL) in Oxfordshire, England, to work together with the instrument responsible at the SXD instrument. We’ve been working on my data analysis, but the main thing we did was do extra measurements on two different laboratory X-ray diffractometers on small shavings of the same LSCO+O crystal that we had on SXD. These data will help me get an even better overview of my superstructures, since the X-ray instruments can measure for higher $$q$$ than what we’ve previously been able to.

The two diffractometers were at ISIS (an Oxford Instruments Gemini diffractometer) and the Harwell Research Complex (an Oxford Instruments SuperNova diffractometer), right on the RAL campus, so it was super convenient. We got so much new data – on several different small pieces of the crystal – and at least some of them have really nice resolution. I can definitely use this further!

The Gemini instrument

I stayed at a cute lille Bed & Breakfast in East Hendred, a short ten minute bus drive from campus. The two cozy pubs provided some awesome meals for my dinners, and I felt super welcome there – I’ll be staying there every time I go to ISIS from now on. The guest house at campus is really, really not worth it compared to this place (it was basically the same price, for a way better room, and way better opportunities for dinner)!

## Beautiful London

On the first day, on my way to Oxfordshire, I took a little detour and spent a few hours in London. It’s the first time I’ve been in the city, and I spent my time walking around, mostly along the Thames – visiting the typical tourist spots like Elizabeth Tower, Trafalgar Square, the Tower Bridge, the Gherkin, and the Millenium Bridge at St. Paul’s Cathedral. I had a great time, and I’ll definitely return one day to have a look at some of the less visited places!

## A little side trip to Oxford

I spent one of my days working at the Bed & Breakfast in the morning, and then taking a short trip to Oxford in the afternoon. I visited some of the old colleges and had coffee and pecan pie at one of the (if not the) oldest coffee shops in Europe – Queen’s Lane Coffee House. I used one of those hop-on-hop-off tourist bus things, and they drove us around and explained how things used to work in the old days of the city. It was really interesting!

I stopped at the botanical gardens and had an ice cream while enjoying the beautiful Spring flowers. I also went to see the beautiful Renaissance dining hall at the Christ Church college, where they filmed the Harry Potter Hogwarts dining hall scenes: despite the long line and too many people, it was kind of fun to see.

## Weekend trip to bird-of-prey park and Stonehenge

On Sunday, April 7th, the local contact took me on a trip to a bird-of-prey park and Stonehenge, just to get out and do something, instead of sitting at the Bed & Breakfast working all weekend. It was super cool – and I’m really glad he suggested it!

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## Flipper2013 workshop at ILL

Since Tuesday, I’ve been at the ILL, attending this years Flipper workshop on the use of polarized neutrons. I was primarily there to learn, since I still haven’t gone much into polarized neutrons, and I have never used them for any experiments.

It was a great workshop, and I learned a lot of new things. I’m still not sure how relevant the things I learned actually are for my PhD project, but at least I met a lot of interesting people. I also presented a poster on the work I’ve done so far on my LCO crystal system – but since we haven’t been able to refine the structure yet, it was mostly a presentation of our awesome data. A few people had a look at it, and openly said that it was going to take a while to get that solved.. so that’s not comforting at all.

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## My first ISIS beamtime

During the last six days, I’ve been in England, more specifically the Rutherford Appleton Laboratory in Oxfordshire, to do measurements on one of our LCO+O crystals (actually the same crystal that we did measurements on at DMC in Switzerland last month). I was at the SXD instrument, a time-of-flight neutron Laue diffractometer, where we measured at five different rotations of the crystal, each for both low temperature and room temperature.

We got a huge amount of data, and mapped out a large volume in reciprocal space. The number of superstructures we saw was really large, and so far we haven’t been able to get a full refinement of the data. The on-site peak integration software was really cool though, and seemed to do the job great – and the instrument scientist was extremely helpful.

All in all, a great experience, and I hope that I (probably with the help of the instrument scientist) will be able to get the superstructures solved.

Of course I also had a few minutes here and there to walk around and take some pictures:

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## Yet another beam time, now with students!

I just got home from Switzerland, once again, this time from a beamtime at the DMC powder diffractometer, where I was measuring on one of our LCO+O single crystal samples, in order to map out part of reciprocal space (both for the crystal aligned in the cb- and the ab-plane). It was some really cool measurements, and I think I’ve already found the front page image for my thesis!

I actually started out the trip with starting up a beam time at the RITA-II instrument, where a YMnO3 sample were to be investigated. That was also really exciting – and that experiment continued during my own DMC beam time as well (sadly I didn’t have time to follow it all the way though, but their results looked really cool!).

Some of the students from the neutron scattering course were down there with us, to follow the two experiments. That was really fun, but I hadn’t expected how hard it was to help them to understand everything, when I didn’t even understand half of it myself! Usually beam times are really tiring, but this really took the price!

The DMC data weren’t really the most perfect data to do structure refinement from (in the cb-plane we only got 12 structural peaks, and some of them were of really bad resolution), but we saw some cool temperature dependencies, and already have some new proposals out for TriCS and other instruments in order to explore those things more. We also got a friendly beam time of two days at the new EIGER instrument, which will be really cool to work with.

This trip also marked the end of the neutron course, although I still need to correct a few reports, and help a few more of the students with their final project. But all in all, it’s been fun teaching in the course, even though it has been quite hard at some times!

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## Total scattering workshop in Santa Fe

From October 14th to 23rd, I was in the states for the first time. I went to Santa Fe (New Mexico) to attend a workshop/conference on total scattering, the Advanced Simulation Techniques for Total Scattering Data conference, arranged by people from Los Alamos National Laboratory, and Oak Ridge National Laboratory.

The actual conference was only from the 16th to the 19th, so I had a few days on each side to go around town and be a bit of a turist. I brought my camera, and got a lot of nice shots (although I’ll have to find the time to actually do the editing and sorting of them later).

My flight there went through Heathrow and Dallas Fort Worth, and turned out to end in a mess – both ways. On the way over there, some very thick fog had hidden Heathrow, and we had to fly in circles – eventually landing in Stanstead to get re-fueled, before we could finally land – more than an hour late – in Heathrow. Of course I missed my Atlantic flight, but luckily I got on the next available one, and still caught my connecting flight in Dallas. My luggage wasn’t as lucky, though.. The people in Dallas were really bad at handling the situation, and it was first when I landed in Santa Fe that people could help me on with the luggage problem (at which time it was too late to send the luggage on from Heathrow, so I had to wait to the evening after). On the way back, our landing in Heathrow got delayed because of the number of planes waiting, and I nearly missed my connecting flight to Copenhagen. The people at Heathrow were nice enough to hand out special orange tickets for people connecting with flights that left soon, but they didn’t take into account that the name ‘Jensen’ is very common in Denmark, and hence stupidly enough only made one ‘Jensen’ ticket, and gave that one to the other ‘Jensen’ Dane that was going on the same plane. So I had to go through the normal procedures, and just caught the plane in time. Of course, my luggage didn’t, again. But oh well, at least I got home.

The conference itself was really nice – both the practical arrangements, the small PDFgui tutorial, the talks, and the trip to Los Alamos, were really well planned and executed. I learned a lot of new information about total scattering, and what it can be used for, and met a lot of cool people. I was really happy to talk to a couple of people from ORNL, to hear how things work over there, since I will be going there in half a year of so.

The turisting part of the trip went nicely as well – I had some fun walking around town, looking at the old buildings and just getting a feel of things. I went to a local supermarket just to see how it was (I was expecting the people packing your groceries for you, but it still just felt creepy to me..), and I went to lots of small restaurants to get some of the New Mexican food (which I was pleasantly surprised about), especially the chile. I even went all the way through town to see the farmers market, and I’m glad I did; You could get to see how they roast the peppers for the chile – that was fun.

Overall, it was a great trip, and I’m really looking forward to going over there again.

A while later, a meeting report was published for the workshop in Neutron News, which can be viewed here. The picture in the top of this blog entry is also from this report.

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## One more workshop on the list – this time on DISCUS

During the full last week, I was in Erlangen (Germany, close to Nürnberg), following a workshop on the diffuse scattering simulation program DISCUS.

It was lots of fun, but I had kind of hoped for something else. A lot of the first day (and sub-sequent days) were used on how to use linux and the terminal (and ranting about how bad windows is – that is, using bad and wrong arguments for it…), instead of introducing the program in a good way. We went through a lot of different tutorials, but a lot of it was very hurried, and not very deep. I guess that at least I got a lot of tools back home with me, so if I really need to use the program (I don’t know if I will, yet), I have something to read up on.

I did buy the DISCUS cook book beforehand, and read a little in it (I didn’t get that far because of me being really busy). I must say that it was a really expensive book, due to the fact that you can only get it i hard-cover, but it is well written – and I think I’ve learned far more from that short period of reading in it, than I did from the actual workshop.

All that said, I would probably recommend people going to the workshop if they actually intend to use the program themselves. It’s really hard figuring out the small logic things on your own – like the fact that they have three different independent programs in the package.

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## OrientExpress beamtime over

I’ve just returned from the Institute Laue-Langevin (ILL) in Grenoble, France, where I’ve been on a super-short beamtime at the neutron Laue instrument OrientExpress. This was my first time to the ILL, and I was going there on my own. That was confusing! The airport in Lyon has really bad signing, but I found my way (after a while of wandering around not understanding anything, I might add..).

I was measuring on two new LSCO crystals, to see how many single crystals was in them. Both of them actually came from one crystal, but it broke into two during the oxygenation process. It seems like they are possibly full single crystals, a great result, but they might have a splitting in the length direction (they are cylindrical) – which is kind of a mess to cut up. I guess I will have to do some X-ray Laue images to see if that is the case.

## The absolutely stunning rail station at Lyon-Saint Exupéry Airport

On the way back home, I went to the airport in Lyon a little early, to go explore the train station connected to the airport. I have never seen a more alien building – it’s absolutely stunning!

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## Another RITA-II beamtime

This was a hard couple of weeks! Just the day after getting home from the DanScatt meeting in Odense, I took a plane to Switzerland super-early in the morning, for a new round of beamtime at the RITA-II instrument at PSI.

Helium and nitrogen refill gives a lot of smoke

With a little help from Christof Niedermayer, I used the first couple of days to get our sample aligned and get it on a new holder (it was already aligned in the ac-plane from the last beamtime, but we needed it in the ab-plane with a certain tilt out of the plane). Astrid showed up Sunday to help. Unfortunately, somewhere in the research phase we had found the wrong diameter of the magnet we were going to use, and it turned out that we had to start all over with a much smaller holder! That was a huge setback, and we had to start almost all over with the alignment. We weren’t done yet when Linda showed up on Monday.

But we did get it working in the end, and did a lot of cool measurements on an incommensurate magnetic peak, and how it changed with applied magnetic field.

## A little weekend trip to Basel

Astrid went home after the first week, leaving Linda and I to finalize the experiment (even though I guess this experiment was mostly for her project). Luckily, it was possible to script a large amount of the scans, and we actually took a whole day off to go to Basel Saturday June 9th. That was a really great little trip, and we saw a lot of fun museums and architecture – especially the Tinguely museum was interesting, with so many odd sculptures!

Another fun thing that happened was that I met Ivana (who I met at the PSI summer school in 2011) in the instrument hall! She was at a beamtime at the SANS-I instrument, doing some measurements that I really didn’t understand. But we had a little time to get some coffee at talk things over, that was nice.

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## PSI detwinning beamtime

Yesterday, I returned from a long week in Switzerland, where I’ve been on a beamtime at the RITA-II instrument at the SINQ neutron source at the Paul Scherrer Institute (PSI).

I was there along with Astrid T. Rømer and Linda Udby, doing measurements on three different LSCO crystals. We tried detwinning them using magnetic fields, but it ended up not working at all.. Week well spent! Well, at least I got some training in aligning single crystals, and we did get some beautiful data.

We’ll have to look at some different techniques for measuring detwinning than neutron scattering (possibly dilatometry), before we want to do anything with neutrons again.

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## Jana2006 workshop all done

Home from the first travel after starting my Ph.D. education! I’ve been to Prague, Czech Republic, the last couple of days, following a two day workshop in the crystal-refinement program Jana2006. The workshop was held at the physics institute in Prague, by some of the people that actually wrote the program.

It was fun times, except when I got lost in the area of my hotel because of numerous roadworks messing up my nice google maps printouts!

Unfortunately we only had those two short days, so I did not manage to get into the center of the city to turist around this time – however, I’ve been to Prague once before, so I guess I didn’t miss out on too much. I really want to go again one day though – it’s such a beautiful city.

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