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Louis-Claude Brunel

Publications and source records attributed to Louis-Claude Brunel.

5 recordsLinked to original sources
arXiv2008

Coherent Manipulation and Decoherence of S=10 Single-Molecule Magnets

We report coherent manipulation of S=10 Fe$_{8}$ single-molecule magnets. The temperature dependence of the spin decoherence time $T_2$ measured by high frequency pulsed electron paramagnetic resonance indicates that strong spin decoherence is dominated by Fe$_{8}$ spin bath fluctuations. By polarizing the spin bath in Fe$_{8}$ single-molecule magnets at magnetic field $B$ = 4.6 T and temperature $T$ = 1.3 K, spin decoherence is significantly suppressed and extends the spin decoherence time $T_2$ to as long as 712 ns. A second decoherence source is likely due to fluctuations of the nuclear spin bath. This hints that the spin decoherence time can be further extended via isotopic substitution to smaller magnetic moments.

cond-mat.mes-hall↗
arXiv2008

A multi-frequency high-field pulsed EPR / ENDOR spectrometer

We describe a pulsed multi-frequency electron paramagnetic resonance spectrometer operating at several frequencies in the range of 110-336 GHz. The microwave source at all frequencies consists of a multiplier chain starting from a solid state synthesizer in the 12-15 GHz range. A fast PIN-switch at the base frequency creates the pulses. At all frequencies a Fabry-Perot resonator is employed and the pi/2 pulse length ranges from ~100 ns at 110 GHz to ~600 ns at 334 GHz. Measurements of a single crystal containing dilute Mn2+ impurities at 12 T illustrate the effects of large electron spin polarizations. The capabilities also allow for pulsed electron nuclear double resonance experiments as demonstrated by Mims ENDOR of 39K nuclei in Cr:K3NbO8.

quant-ph↗
arXiv2007

Sub-MHz Linewidth at 240 GHz from an Injection-Locked Free-Electron Laser

Radiation from an ultra-stable 240 GHz solid-state source has been injected, through an isolator, into the cavity of the University of California Santa Barbara (UCSB) MM-wave free-electron laser (FEL). High-power FEL emission, normally distributed among many of the cavity's longitudinal modes, is concentrated into the single mode to which the solid state source has been tuned. The linewidth of the FEL emission is 0.5 MHz, consistent with the Fourier transform limit for the 2 microsecond pulses. This demonstration of frequency-stable, ultra-narrow-band FEL emission is a critical milestone on the road to FEL-based pulsed electron paramagnetic resonance spectroscopy.

cond-mat.other↗
arXiv2001

Mixed-Valence Tetranuclear Manganese Single-Molecule Magnets

The preparations, X-ray structures, and detailed physical characterizations are presented for two new mixed-valence tetranuclear manganese complexes that function as single-molecule magnets (SMM's): [Mn4(hmp)6Br2(H2O)2]Br2.4H2O and [Mn4(6-me-hmp)6Cl4].4H2O, where hmp- is the anion of 2-hydroxymethylpyridine and 6-me-hmp- is the anion of 6-methyl-2-hydroxymethylpyridine.

cond-mat↗