Stephen Hill

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Electron Magnetic Resonance Highlights,
Progress and Vision

• Stephen Hill

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New/Unique Instrumentation
Multiple spectrometers and multiple magnets,
incl. compatibility with ALL resistive magnets
for c.w. EPR (i.e. not pulsed)
NEW
UNIQUE Pulsed EPR at 120 GHz, 240 GHz and 336
GHz with lt100ns time resolution
UNIQUE Pulsed Electron-Nuclear Double Resonance
- 120 GHz, 240 GHz 336 GHz
UNIQUE Fully contiguous frequency coverage from
8 GHz to 1 THz
NEW
UNIQUE Small single-crystal capabilities
(cavity-based), two-axis rotation
NEW
UNIQUE Combination with full suite of magnets
in Tallahassee
ALSO NEW IN 2009 Mössbauer spectroscopy at
liquid helium temperatures and 9T COMING SOON TO
A LAB NEAR YOU 9/5/1 T Vector
magnet HiPER-II for 1ns pulsed EPR
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2009 PUBLICATIONS (so far)
In 2009 (reported so far) 25 Publications 5
PRL, 4 PRB, 3 JACS, 3 Inorg. Chem., 1
Biochemistry In 2008 47 Publications 1 Nature,
1 Nature Phys., 5 PRL, 5 PRB, 2 JACS, 9 Inorg.
Chem. In 2007 32 Publications 3 PRL, 4 JACS, 3
PRB, 4 Inorg. Chem., 1 Biochemistry
2009 Highlights

• Bertaina, S. Chen, L. Groll, N. van Tol, J.
  Dalal, N.S. and Chiorescu, I., Multiphoton
  Coherent Manipulation in Large-Spin Qubits, Phys.
  Rev. Lett., 102 (5), 050501 (2009)
• Galiano, L. Ding, F. Veloro, A.M. Blackburn,
  M.E. Simmerling, C. and Fanucci, G.E., Drug
  Pressure Selected Mutations in HIV-1 Protease
  Alter Flap Conformations, J. Am. Chem. Soc., 131
  (2), 430-431 (2009)
• Henderson, J.J. del Barco, E. Koo, C. Hill,
  S. Feng, P.L. and Hendrickson, D.N.,
  Manifestation of Spin Selection Rules on the
  Quantum Tunneling of Magnetization in a Single
  Molecule Magnet, Phys. Rev. Lett., 103, 017202
  (2009)
• McCamey, D.R. van Tol, J. Morley, G.W. and
  Boehme, C, Fast Nuclear Spin Hyperpolarization of
  Phosphorus in Silicon, Phys. Rev. Lett., 102,
  027601 (2009)
• Ozarowski, A. Szymanska, I.B. Muziol, T. and
  Jezierska, J., High-Field EPR and Magnetic
  Susceptibility Studies on Binuclear and
  Tetranuclear Copper Trifluoroacetate Complexes.
  X-ray Structure Determination of Three
  Tetranuclear Quinoline Adducts of Copper(II)
  Trifluoroacetate, J. Am. Chem. Soc., 131,
  10279-10292 (2009)
• Takahashi, S. van Tol, J. Beedle C.C.
  Hendrickson, D.N. Brunel, L.C. and Sherwin,
  M.S., Coherent manipulation and decoherence of
  S10 single-molecule magnets, Phys. Rev. Lett.,
  102 (08), 087603 (2009)
• Stoll, S. Gunn, A. Brynda, M. Sughrue, W.
  Kohler, A.C. Ozarowski, A. Fisher, A.J.
  Lagarias, J.C. and Britt, R.D., Structure of the
  Biliverdin Radical Intermediate in
  PhycocyanobilinFerredoxin Oxidoreductase
  Identified by High-Field EPR and DFT, J. Am.
  Chem. Soc., 131 (5), 1986-1995 (2009)

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MEET SOME OF OUR RECENT USERS EARLY CAREER
SCIENTISTS
Song I Han UCSB, Chemistry
Irinel Chiorescu FSU - Physics
Enrique del Barco UCF - Physics
Gail Fanucci UF - Chemistry
Adam Viege UF - Chemistry
NEW
NEW TO EMR
Christophe Boehme U. Utah, Physics
Euan Brechin Edinburgh, Chem.
Jeremy Smith New Mexico State, Chem.
Suchitra Sebastian Cambridge
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RECENT GROUP MEMBERS
Gavin Morley LCN, UCL/Imperial
Saritha Nellutla NCSU, Chemistry
Sylvain Bertaina CNRS, Marseille
Louise Brown Macquarie U.
Saiti Datta Postdoc., U. TN
Sergei Zvyagin EPR director, Dresden
Susumu Takahashi iQCD UCSB FEL
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Educational activities/studentsThe Pulsed EPR
Summer School

• 21 participants.
• Students/postdocs from Physics, Chemistry and
  Biology PhD programs.
• Three students from UF.
• Lecturers from NHMFL, FSU and UF theory and
  hands-on experience.
• NHMFL also runs a summer school on high-field
  techniques.

Based on the success of this first workshop, we
plan to hold similar events in coming years that
will be open to members of the EMR community in
the US and overseas.
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International ActivitiesEducation and Technique
Development

• NSF International Collaboration in Chemistry
  (450k for 3 yrs, PI Hill, co-PIs Krzystek
  and Tozer), grant CHE 0924374, together with U.
  of Edinburgh to develop EPR under pressure. 10k
  per year for student and postdoc exchanges.
  Identical funding in Edinburgh

• Developing a Materials World Network Proposal
  together with UCF, U. Valencia and U. Zaragosa
  mainly for student exchange.

• About to start major collaboration with St.
  Andrews, including exchange of personnel Hans
  van Tol is there now.

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Conference activitiesExpanding the EMR user base
Orlando 2012
2010 Orlando

• Quantum Coherent Properties
• of Spins Dec. 2009

• Quantum Properties Magnetic Molecules Nov. 2008
• Participation in many other meetings

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PHYSICS HIGHLIGHTS
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• New method for obtaining nuclear
  hyper-polarization via optical injection of hot
  carriers
• Probed by electrically-detected
  high-field/high-frequency (240 GHz) EPR.
• 2.5 minutes of pumping at 1.37 K to attain
  nuclear temperature of -5 mK.
• Potential applications in nuclear imaging and
  quantum information.

31P in Si
240 GHz
McCamey et al., Phys. Rev. Lett. 102, 027601
(2009). Partially supported by the NHMFL visiting
scientist program.
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Multiphoton Coherent Manipulation in Large-Spin
Qubits
S. Bertaina, I. Chiorescu et al., Phys. Rev.
Lett. 102, 050501 (2009)

• S 5/2 MnII ions diluted into an MgO crystal.
• Combination of weak anisotropic interactions and
  adjustable field-orientation allows tuning from
  harmonic to anharmonic spectrum.
• Decoherence effects are strongly suppressed (Rabi
  oscillations at 300 K).
• Consecutive microwave pulses of varying
  intensities/durations couple different spin
  states via controlled multi-photon processes.
• May simplify implementation of proposed quantum
  algorithms.

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Revealing Intrinsic Quantum Properties of Simple
Molecular Nanomagnets with Novel Topologies
Hysteresis
Chirality ? B43 Sz(S3 S-3)
EPR
Mn3
Chiral molecule NEt43Mn3Zn2(salox)3O(N3)X2
with X Cl/Br
Clear observation of spin-selection rules ?
almost no disorder
Henderson, del Barco, Hill, Stamp, Hendrickson,
et al., Phys. Rev. Lett. 109, 017202 (2009)
Feng, del Barco, Hill, Hendrickson et al.,
Inorg. Chem. 48, 3480 (2009).
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Revealing Intrinsic Quantum Properties of Simple
Molecular Nanomagnets with Novel Topologies

• A 2nd example addresses the role of antisymmetric
  exchange in molecular magnets.
• It is shown that such terms cannot mix states of
  opposite parity in a centrosymmetric molecule,
  even if antisymmetric interactions are allowed
  locally between individual sites on the molecule.

Ramsey, Hill, del Barco, Nature Physics 4, 277
(2008)
del Barco, Hill and Hendrickson, Phys. Rev. Lett.
109, 059701 (2009).
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Repeat Offender Diamond to Iron High magnetic
fields ( low T) quench spin decoherence
Magnetic molecules Coherence Window
Fe8, S 10
240 GHz 11.5 K
S. Takahashi, van Tol, Hendrickson et al., Phys.
Rev. Lett. 102, 087603 (2009).
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CHEMISTRY AND BIOCHEMISTRY
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Light Harvesting
Structure of Biliverdin Radical Intermediate in
PcyA by HFEPR
S. Stoll, A. Gunn, M. Brynda, W. Sughrue, A. C.
Kohler, A. Ozarowski, A. J. Fisher, J. C.
Lagarias, R. D. Britt (PI), Department of
Chemistry, University of California, Davis
NHMFL.

• Photosynthesis in cyanobacteria more efficient
  than in plants
• Involves electron proton transfer via radical
  intermediates
• Mechanism poorly understood nature of
  freeze-quenched radical intermediates can be
  determined by HFEPR
• Only f gt 400 GHz EPR provides necessary g
  resolution
• Information not accessible via x-ray techniques

S. Stoll et al., J. Am. Chem. Soc. 2009, 131(5),
1986-1995. Funded by NIH (GM073789, GM068552)
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EMR Facility Future Directions
The HIPER Project - nanosecond pulse EPR
In collaboration with the University of St.
Andrews (G. Smith) and Thomas Keating LtD (R.
Wylde), UK
Harness well-developed quasi-optical mm-wave
technologies (95GHz above) that provide a
quantum leap in the performance of pulse ESR
systems

• 1 kW, 95 GHz amplifier
• Future NHMFL version at f gt 200GHz

Witchs hats are high performance loads that
render the propagation system dead

• Manipulate and detect spins on nanosecond and
  sub-nanosecond timescales
• Demonstrate significant gains in sensitivity for
  pulse EPR with low deadtime

HiPER kW pulses as short as 800 ps ? can
operate over 1GHz bandwidth ?ns deadtime ?
reflected pulses attenuated -80dB within 1-2 ns!
THIS IS ONLY POSSIBLE OPTICALLY AND ONLY POSSIBLE
AT 95 GHz AND ABOVE
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EMR Facility Future Directions
The HIPER Project - nanosecond pulse EPR
In collaboration with the University of St.
Andrews (G. Smith) and Thomas Keating LtD (R.
Wylde), UK
Increased orientation selectivity at W-band
State-of-the-art commercial system
Polyhach, et al., JMR, 185 (2007), pp.118-129
Implications also for FT EPR on biologically
relevant labels Bringing the NMR Paradigm to
EPR Dynamic Nuclear Polarization enormous
implications for NMR Coherent spin manipulations
in solids (quantum information/quantum matter)
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USER STATISTICS - 2007 2008
Total users (PIs and persons present at the NHMFL)
2007 101
2008 99
Jurek Krzystek was on sabbatical during 1st half
of 2008.
Total numbers and categories of user groups in CY
2008
Total
Total number of user groups in 2008 47
New external user groups 21
Users from affiliated NHMFL groups 4
Internal user groups 4
International (non-US) user groups 23
One request was not granted
We do not compile statistics (complex process
see later) until after Jan. 1, so cannot present
hard data for 2009.
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USER STATISTICS - 2007 2008
Total users (PIs and persons present at the NHMFL)
2007 101
2008 99
Jurek Krzystek was on sabbatical during 1st half
of 2008.
Total numbers and categories of user groups in CY
2008
Total
Total number of user groups in 2008 47
New external user groups 21
Users from affiliated NHMFL groups 4
Internal user groups 4
International (non-US) user groups 23
One request was not granted
But I have already counted 22 new user groups
(very rough count) for 2009, in addition to many
existing users.