2008 CCMS Summer Lecture Series
The Lectures:
Greg Stewart's Lecture (PDF)Andrew Rinzler's Lecture (PDF)
2008 Schedule
Summer 2007 Lecture
The Preparation and Characterization of (Real) Materials for Research – a University of Florida Perspective
Prof. G. R. Stewart
OVERVIEW
These lectures will introduce students to both various methods of how to prepare samples (including examples from each lab in the Physics department plus an overview of the work on campus) and how to characterize their samples and some of the tricks/pitfalls/opportunities of these methods. The lectures will also provide the faculty attending with an overview of what their colleagues are doing and a review of a broad range of characterization methods, with a focus on those done in-house and at the Major Analysis Instrumentation Center in the materials science department.
LECTURE PLAN
(starting from July 21, 2008, 75 minutes per lecture)
Topic 1 (2 lectures): Overview of sample prep in the Physics Dept. (highly correlated f-electron systems: poly- and single-crystal; manganites; high Tc superconductors; proteins; thin films and restricted dimension systems; single molecule magnets; organic conductors; liquid 4He and 3He, solid 3He; nanoparticles; carbon nanotubes; solid hydrogen; quasi-one-dimensional antiferromagnets; conducting polymers). Also, materials research on campus: an overview will be presented.
Topic 2 (3 lectures): The history of materials characterization, starting with the ancients and gold. Tricks of the trade, useful in the majority of sample preparation, for making high quality samples: e.g. assuring purity (both trace atom impurities and unwanted phases), limiting defects or putting defects in intentionally, controlling composition (nominal composition vs actual composition), dealing with differing vapor pressures of the constituent elements, annealing, . . . . Measurement techniques for checking sample quality, e.g. x-ray diffraction (poly- and single-crystal techniques) and determination of phase impurity and lattice parameter(s); electron microprobe for determining composition; metallography techniques for determining phase purity – combined with microprobe; SEM and TEM; surface characterization of films using Auger spectroscopy; other methods. A one hour tour of MAIC will take place, with several 15 minute talks by their staff explaining the available techniques. Several in-depth examples will illustrate how real samples can have hidden, difficult-to-determine extrinsic problems, e. g. nominal CePt3Si with Ce2Pt15Si7 as a second phase; manganites and compositional inhomogeneity; thin films and their problems (epitaxy, homogeneity, surface vs 'bulk', …), others.
Topic 3 (3 lectures): Now that the sample has been prepared and characterized (but not before!), it's time to do some measurements to answer scientific questions. In-depth lectures on the following measurement techniques, as a subset of the multitudinous techniques carried out on campus, will be given:
a. Resistivity (1 lecture) (ac vs dc, contacting the sample, getting to low temperature without contact and sample heating, interpretation of the data, what constitutes a broad enough temperature regime to determine a in ρ = ρ0 + ATa, meaning of various temperature dependences and relevant theories, . . . )
b. Magnetic susceptibility (1 lecture) (ac vs dc, cantilever, Quantum Design machines, low field vs high field, NHMFL facilities, the various theoretically predicted temperature dependences, determination of the effective magnetic moment, μeff, from a Curie-Weiss plot, superconductivity, determination of the upper critical field, magnetism, low temperature – the final frontier for understanding many physics questions, how to interpret magnetization data, . . . )
c. Specific heat (2 lectures) (history, various measurement methods including quasi-adiabatic, ac, time constant methods. Quantum Design Machines. Micro- and nano-calorimetry, measurement in high magnetic fields, measurements under high pressures, the Sommerfeld coefficient γ and its meaning in numerous physics questions, the Debye temperature, temperature dependences of magnon contributions to the specific heat, transitions – first, second, and third order (?), thermometry – another final frontier, standards.
TENTATIVE SCHEDULE
The lecturer will organize additional discussion and homework solving sessions on the first day
| Lecture 1 | July 21 (M) 10:00 - 11:30 |
| Lecture 2 | July 22 (T) 10:00 - 11:30 |
| Lecture 3 | July 23 (W) 9:30 - 10:45
July 24 (Th) OFF |
| Lecture 4 | July 25 (F) 10:00 - 11:30 |
| Lecture 5 | July 28 (M) 10:00 - 11:30 |
| Lecture 6 | July 29 (T) 10:00 - 11:30 |
| Lecture 7 | July 30 (W) 9:30 - 10:45
July 31 (Th) OFF |
| Lecture 8 | Aug. 1 (F) 10:00 - 11:30 |