|
Condensed Matter Physics at Extreme Conditions: High B, and Low T*
Alex H. Lacerda 1, 2 National High Magnetic Field Laboratory
1 National High Magnetic Field
Laboratory, Pulsed Field Facility, Los Alamos National Laboratory
2 National High Magnetic Field Laboratory, Florida State University
Magnetic fields along with temperature and
pressure are the most important thermodynamic parameters used to probe
matter. The National High Magnetic Field Laboratory (NHMFL) mission is
to maintain a strong research program and an international users program
centered on the strongest magnetic fields available. Pressure to 40kBar,
DC to terahertz spectroscopy, and 300K to well above ambient
temperatures and more provide necessary tools for thorough exploitation
of our unique magnet resources. Combining structure and phonon studies
via elastic and inelastic neutron and light scattering round out a
powerful suite of capabilities in use, or under development at the NHMFL.
The three sites of the NHMFL located at Florida State University
(Tallahassee), University of Florida (Gainesville), and Los Alamos
National Laboratory (LANL) comprise the primary high field user facility
of the United States. The current experimental portfolio includes DC
magnetic fields to 45T (hybrid magnet) and 33T (resistive), pulsed
magnets to 70T, and a newly commissioned 900MHz NMR magnet. We focus
here on current and future plans for high-magnet-field technology and
recent scientific highlights.
The international user program at the NHMFL continues to grow, assisted
by highly talented in-house scientists, new laboratory infrastructure,
and the continuing development of experimental techniques to measure
physical quantities rarely or never before measured in extremely high
magnetic fields.
Materials' strengths have limited the development worldwide of high
magnetic fields, particularly short-pulse magnets beyond the 80T range.
The NHMFL continues to pursue magnet engineering of single-shot
destructive magnets and enhancement of routinely-available peak field
and repetition rate of multi-shot magnets. Recently we achieved 75T in a
short pulse duplex magnet (15mm bore, 10ms). This particular magnet is
part of our effort to develop a 100T non-destructive magnet.
During the last couple of years an emerging theme relates to
understanding magnetically-induced new phases of condensed matter. Using
neutrons (and soon, x-rays) combined with sound-speed measurements to
determine phonons and structure has, in conjunction with NHMFL magnetic
fields, provided new insights into plutonium science as well as many
other materials. We also discuss lattice contributions to quantum
criticality effects via Grunesisen physics and explore recent results in
high Tc superconductors and strongly correlated materials.
* The NHMFL is supported by the National
Science Foundation, the US Department of Energy, and the State of
Florida |