Physicist Chris Landee and student Alex Shapiro worked together to create new materials with which to explore the magnetic properties of spin ladders.
Meet the researchers: A very nice community
Interview with Professor Chris Landee and Alex Shapiro
Physicist Chris Landee and Alex Shapiro '05, a native of Ukraine, worked together to develop new materials with interesting magnetic properties. In a 2005 interview, summarized below, Landee discusses how his interests straddle the fields of physics and chemistry, and physics major Shapiro talks about his research experience.
Chris, how did you become interested in physics?
I should also talk about how I got interested in chemistry, because as well as being a professor of physics, I am an adjunct faculty member in chemistry.
My father was a chemist, and the last thing I wanted anything to do with was
chemistry! I didn't like high school chemistry very much. Too many facts to
remember, and not enough of the bigger picture! I didn't understand how those facts were pulled together.
Then I took physics. The wonderful thing about physics is that at the end of four years of study you can write down just about everything that you've learned on a 3 x 5 inch card! You need a few basic equations, the idea that heat is a form of energy and Maxwell's equations for electricity and magnetism, a few constants like the speed of light and Planck's constant, and that's it. Everything explains everything else. Physics seems to unlock the secrets to so many things. I like to understand why things happen the way they do. I also like to be able to make quantitative measurements that allow you to say 'yes, this is true,' and 'no, that's not true.'
Then I went to graduate school at the University of Michigan and prepared to do a
physics dissertation on some interesting properties of super fluid helium. But that was in 1970, when the war in Vietnam was going badly, the country was running large deficits, and the Republican president cut the National Science Foundation budget in half. The financial support for the kind of research I wanted to do disappeared.
But I was interested in properties of materials, and was told of a thermodynamics
specialist in the chemistry department who measured the temperature dependent properties of electric or magnetic materials. I talked to him and the science seemed interesting. AND he had funding from what at the time was called the Atomic Energy Commission. So I spent four years in the chemistry department.
After completing my Ph.D., I found a wonderful post-doc position with a physical
chemist, a crystallographer interested in magnetism. He wanted to know what it was
about a chemical structure that would make some materials magnetic, some
ferromagnetic, and some anti-ferromagnetic. He wanted to work with me because I
had a background in physics and four years of experience working with chemists. So
I spent the next four years working with him.
And then you came to Clark?
Yes, I came to Clark and brought my interest in magnetism, and in making new
magnetic material—material that doesn't exist in nature and that behaves the way
theory predicts. Then chemist Mark Turnbull, who's also interested in magnetism,
came to Clark in 1987. We've been working together steadily for the past 15 or so
years. It's been a good adventure.
Does your current research continue to focus on developing new materials with
different kinds of magnetic properties?
Yes. For about five years now we've been trying to make molecular spin ladders.
These are magnetic chains that are coupled together in a sort of ladder formation,
and they have some fascinating magnetic properties. But there are very few such
materials known. Two that have been studied the most have in fact been shown not
to be ladders at all. They're more complicated than that. Of the spin ladders that can be completely magnetized, more than half of them have been developed here at Clark.
How does Alex's work fit in?
When Alex joined our research group, we wanted to give him a fairly straightforward project to start with. We decided to have him take one of the spin ladder compounds and break it down into just one rung, so we could make an independent measurement of what's happening in a single magnetic chain. Later we could think about how to stitch it together with another chain.
So we gave Alex this project, thinking it would be a piece of cake! Just mix A with B and wait for the water to evaporate. Well that was a rude introduction. It turned out to be very difficult. Alex kept getting a different material every time he ran the procedure. That's very bad. Science is supposed to be about what's reproducible. And we couldn't grow crystals, and without crystals we couldn't really know the structure of the material. So after having done this for one summer, his junior year, and part of the following summer, Alex was extremely frustrated and had made a lot of non-reproducible junk!
We decided to try something different by giving the two molecules we were working
with, Quinoline and 2,3-dimethylpyridine, an electronic charge before connecting one or the other with either copper chloride or copper bromide. There are four possible combinations (copper chloride with quinoline or 2,3- dimethylpyridine, then copper bromide with the same two molecules), and it turned out that all are marvelously successful materials! As soon as Alex added the electronic charge, he grew beautiful crystals.
Alex: The copper quinolinium bromide turned out to have copper bromide units stacked in widely spaced layers, which is exactly what we were looking for. If the layers are too close together, they interact with each other. We're only interested in magnetic interactions within the layers, not between them.
In addition, one of the compounds (copper 2,3-dimethylpyridinium bromide) turned out to be a spin ladder and to have a stronger interaction along the rails than the rungs. Only one of the previously known ladders has it this way.
Alex, how did you become involved with this research?
One of my professors suggested that I get involved in an independent project of
some sort, and Professor Landee had an opening in his lab.
Could you comment on the kind of learning that takes place doing research versus in a more traditional classroom setting?
When you're doing research you work more independently. It makes you think more
clearly and learn to make your own decisions. I would recommend research
participation. It's very helpful in the learning process.
Chris, does the physics department encourage students to become involved in
The opportunity to participate in research as an undergraduate is the advantage of
studying physics at Clark. In fact, we have a requirement that each student must do at least one semester of directed research. We also encourage all physics majors to spend at least one summer on campus—ten weeks—working with a research group. Money for student fellowships is available through the department. Also, in the past, there's been money from the National Science Foundation that supports summer research experience.
Summer is a good time to start participating, because there are people around to
teach students the lab techniques they need. Then, during the academic year when
professors are much busier, the students have the skills to work independently. They know the tools and techniques. Alex, for example, has become an expert at collecting data, running measurements, analyzing data, and then trying to fit the results to various mathematical models. The models help us understand in a qualitative and quantitative sense exactly what's going on in the materials. During the past eight months, Alex has pretty much been working on his own. He comes in periodically and tells me what he's got, and what he thinks it means, and then we talk about what he should do next.
Does the physics department offer a Ph.D. program?
Yes, and between the faculty, graduate and undergraduate students we have a very nice community. And despite our small size we maintain a high level of research activity, while at the same time supporting a significant amount of undergraduate teaching. And teaching is something that we all want to do. That's why we're at Clark, and it works well.
Our students get good jobs. My colleague Chuck Agosta is the one university professor in the United States that trains his students how to generate and work in high magnetic fields. His students are hired routinely by national labs as staff scientists. One of Arshad Kudrolli's former students recently completed a post-doctorate at MIT and has just accepted a position as assistant professor of biophysics at Brandeis University. So we're very pleased by the quality of the students that we turn out.
Professor Chris Landee and Alex Shapiro