Steven D. Jacobsen
Assistant Professor
Department of Earth and Planetary
Sciences
Northwestern
University
Tel: 847.467.1825
My research is
aimed largely towards understanding the origin and properties of Earth and
planetary materials through experiment. The physical properties of minerals are
controlled by their crystal structures. Mineral
physics links what can be probed at the atomic level, to geophysical
processes that are observed at the global scale, especially through seismology.
This link, between atoms and macroscopic observables is central to my studies
on materials ranging from the major Earth-forming minerals
to unusual phases with surprising structures and advanced technological
materials with novel properties.
My Research is supported by a Fellowship for Science and Engineering by the David and Lucile Packard Foundation and National Science Foundation Grants EAR-0721449 (Geophysics Program), EAR-0651173 (Instrumentation and Facilities) and a Faculty Early Career Development Award (CAREER) EAR-0748707. Support is also provided by the Carnegie/DOE Alliance Center (CDAC), a Stewardship Science Academic Alliance Program of the Department of Energy and the National Nuclear Security Adminsitration.
Recent Publications Complete List
- Crowhurst, J.C., J.M. Brown, A.F. Goncharov and S.D. Jacobsen (2008) Elasticity of (Mg,Fe)O through the spin transition of iron in the lower mantle. Science, 319, 451-453. PDF
- Goncharov,
A.F., V.V. Struzhkin and S.D.
Jacobsen (2006) Reduced radiative conductivity of low spin (Mg,Fe)O in
the lower mantle. Science, 312,
1205-1208. PDF
- Goncharov, A.F., B.D. Haugen, V.V. Struzhkin, P. Beck and S.D. Jacobsen (2008) Radiative conductivity in the Earth's lower mantle. Nature, 456, 231-234.
- Lin,
J.F., G. Vanko, S.D. Jacobsen, V. Iota, V.V. Struzhkin, V.B. Prakapenka, A. Kunznetsov and C.-S. Yoo (2007) Spin transition zone in Earth's lower mantle. Science 317, 1740-1743. PDF
- Jacobsen, S.D. (2006) Effect of water on the equation of state
of nominally anhydrous minerals. Reviews
in Mineralogy and Geochemistry, 62, 321-342. PDF
-
- Jacobsen, S.D., F. Jiang, Z. Mao, T.S. Duffy, J.R. Smyth, C.M. Holl, and D.J. Frost (2008) Effects of hydration on the elastic properties of olivine. Geophysical Research Letters, 35, L14303. PDF
Earth's Deep Water Cycle
Steven D. Jacobsen and Suzan van der Lee, Editors
I employ an array of methods including X-ray and
neutron diffraction, ultrasonics, visible-IR absorption and Raman spectroscopy
using either laboratory or synchrotron radiation sources in order to gather
information on the properties of Earth materials than can be directly compared
to seismic observables. My laboratory is equipped for high-pressure and
high-temperature studies of materials to conditions deep in the lower mantle
(down to ~2900 km depth). Ultimately, results from mineral physics are used to
interpret the mineralogy, composition, and evolution of the Earth and planetary interiors.
I am developing
a high-frequency acoustic method called gigahertz (GHz)
ultrasonic interferometry. This ultrasonic probe has been interfaced with
the diamond-anvil cell (DAC)
in order to monitor compressional and shear-wave velocities in single-crystal
samples that were previously too small for ultrasonic methods. GHz-frequency shear waves are produced by
P-to-S conversion inside a single-crystal gem.
This year, signals have been obtained in samples as thin as 20 microns, or more
than 4 times thinner than a human hair. This is of particular application to
those high-pressure phases that can now be synthesized in large-volume presses,
such as the 5000-ton press at
Bayerisches Geoinstitut, where I synthesize most of my samples. The acoustic
measurements are made along with in-situ X-ray diffraction at high-pressures
inside a new ultrasonic diamond-anvil cell.
Single-crystal elastic wave velocities (and the density) are used to obtain the
elastic tensor (Cij),
relating stress to strain in elastic solids.
Solid-Earth geophysics and geochemistry, mineral physics, high-pressure mineralogy
and crystallography, crystal chemistry, mantle petrology, Earth and planetary
interiors, hydrogen storage in the mantle, behavior and consequences of iron in
minerals, equations of state, elasticity, compressibility, thermal expansion,
hydrogen bonding, single-crystal synthesis, novel materials
Methods
Single-crystal X-ray and neutron diffraction, ultrasonics, infrared
spectroscopy, Raman spectroscopy, TEM, diamond-anvil cells (for in-situ measurements up to 100 GPa and
4000 K), multi-anvil press (for high P-T synthesis up to 25 GPa and 2300 K).
Current Courses at Northwestern
Earth 102-The Future of Renewable Energy
Earth 300-Mineralogy and
Petrology
Education
Ph.D. Geophysics; University of Colorado
M.S. Geology;
B.A. Geology, minor Mathematics;
Assistant Professor, 2006 - present
Department of Earth and Planetary Sciences, Northwestern University,
Research Scientist (Principal Investigator), 2005 -
2006
Carnegie Institution of
Barbara McClintock Fellow; 2005
Carnegie Institution of
Alexander von Humboldt Fellow and Research Associate,
2002 - 2004
Bayerisches Geoinstitut,
CIRES Graduate Research Fellow, 1999 - 2000
Cooperative Institute for Research in
Environmental Sciences (CIRES) and Department of Geological Sciences,
University of
Any opinions, findings, and conclusions or recommendations expressed in
this material are those of the author(s) and do not necessarily reflect the
views of the National Science Foundation.