FY2010 - Oak Ridge National Laboratory

Director’s R&D Fund—
Neutron Sciences
timestamps are recorded directly from the time clock on the sample environment computer, which is
synchronized with the central timing computer, to ensure the same timestamps from neutron events. With
the new developed software VDRIVE, neutron event data with proton charges and sample environment
data can be reduced and synchronized to various temporal resolutions from sub-seconds and beyond.
With those newly developed capabilities, we have demonstrated the fundamental concept of
asynchronous neutron diffraction measurements by example of continuous heating experiment of phase
transition of textured titanium alloy, a charge and discharge phenomenon in a large format prismatic
battery, and lattice strain evolutions of a model stainless steel under low-cycle fatigue. Temporal
resolutions of these initial experiments are demonstrated from minutes to millisecond.
Information Shared
An, K., H. D. Skorpenske, A. D. Stoica, D. Ma, K. L. Wang, and E. Cakmak. 2011. “First in situ lattice
strains measurements under load at VULCAN.” Metallurgical and Materials Transactions A 42(1),
95–99.
05432
The Search for Common Themes in Unconventional
Superconductivity: Spin Excitations in Organic Superconductors
Andrew D. Christianson, Georg Ehlers, Mark D. Lumsden, Thomas A. Maier, David Mandrus,
Stephen E. Nagler, and Cuihuan Wang
Project Description
Organic metals, molecular magnets, and superconductors have attracted considerable attention due to the
possibility of designing materials for specific applications with the vast array of organic complexes
available through modern synthetic techniques. Despite this, very little is known about the pairing
mechanism or the magnetic interactions found in organic superconductors and related molecular magnets.
Here we propose to remedy this through inelastic neutron scattering studies of the excitations in organic
superconductors and closely related materials with particular emphasis on the evolution of the spin
excitations from the antiferromagnetic to the superconducting side of the phase diagram. The project
consists of three components: (1) sample synthesis and characterization, (2) theory and simulation, and
(3) experimental inelastic neutron scattering studies. The combination of these components will lead to an
unprecedented understanding of the excitations in organic superconductors and may yield common
themes for the investigation of unconventional superconductivity.
Mission Relevance
The project will provide key additional knowledge of the physical behavior of organic superconductors
and related molecular magnets and will contribute to the broader understanding of unconventional
superconductivity and magnetism and consequently has the potential to contribute to a materials-based
solution to the energy crisis. As such this project has direct relevance to the mission of the Division of
Materials Sciences and Engineering in the DOE Office of Basic Energy Sciences.
Results and Accomplishments
We have made significant strides in the synthesis of deuterated organic superconductors and organic
charge coordination polymers. Samples of deuterated CuF2(H2O)2-pyz and κ-(BEDT-TTF)2X (X = Cl, Br)
56