In: Nature Materials, 2017, vol. 16, no. 4, p. 467–473
Photochemical reactions are essential to a large number of important industrial and biological processes. A method for monitoring photochemical reaction kinetics and the dynamics of molecular excitations with spatial resolution within the active molecule would allow a rigorous exploration of the pathway and mechanism of photophysical and photochemical processes. Here we demonstrate that...
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In: Physica Scripta, 2014, vol. 88, no. 6, p. 068511
We discuss the general principles of laser-excited muon pump–probe spin spectroscopy (photo-μSR), including the historical origins of the technique, and discuss the overall experimental method. We review examples of past work using this technique, then discuss the future upgrade of the HiFi spectrometer with a high-power laser system. In particular, we note that performing photo-μSR...
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In: Physical Review Letters, 2013, vol. 110, no. 21, p. 216602
Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence...
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In: Physical Review B - Condensed Matter and Materials Physics, 2012, vol. 86, no. 14, p. 144112
Using muon spin rotation (μSR) we investigated the magnetic and superconducting properties of a series of Ba(Fe1−xCox)₂As₂ single crystals with 0≤x≤0.15. Our study details how the antiferromagnetic order is suppressed upon Co substitution and how it coexists with superconductivity. In the nonsuperconducting samples at 0
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In: Physical Review B: Condensed Matter and Materials Physics, 2011, vol. 84, no. 8, p. 085209
Electron spin relaxation rate (eSR) is investigated on several organic semiconductors of different morphologies and molecular structures, using avoided level crossing muon spectroscopy as a local spin probe. We find that two functionalized acenes (polycrystalline tri(isopropyl)silyl-pentacene and amorphous 5,6,11,12- tetraphenyltetracene) exhibit eSRs with an Arrhenius-like temperature...
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In: Nature Materials, 2011, vol. 10, p. 39–44
Spintronics has shown a remarkable and rapid development, for example from the initial discovery of giant magnetoresistance in spin valves (Baibich, M. N. et al. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett. 61, 2472–2475, 1988) to their ubiquity in hard-disk read heads in a relatively short time. However, the ability to fully harness electron spin as...
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In: Nature Materials, 2009, vol. 8, p. 310 - 314
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In: Nature Materials, 2009, vol. 8, p. 109 - 114
Electronic devices that use the spin degree of freedom hold unique prospects for future technology. The performance of these 'spintronic' devices relies heavily on the efficient transfer of spin polarization across different layers and interfaces. This complex transfer process depends on individual material properties and also, most importantly, on the structural and electronic properties of the...
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In: Physical Review Letters, 2008, vol. 101, no. 9, p. 097010
Muon spin rotation experiments were performed on the pnictide high temperature superconductor SmFeAsO1-xFx with x=0.18 and 0.3. We observed an unusual enhancement of slow spin fluctuations in the vicinity of the superconducting transition which suggests that the spin fluctuations contribute to the formation of an unconventional superconducting state. An...
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In: Physical Review Letters, 2008, vol. 100, p. 116601
Muon spin relaxation has been used to probe the charge carrier motion in the molecular conductor Alq₃ (tris[8-hydroxy-quinoline] aluminum). At 290 K, the magnetic field dependence of the muon spin relaxation corresponds to that expected for highly anisotropic intermolecular electron hopping. Intermolecular mobility in the fast hopping direction has been found to be 0.23±0.03 cm² V⁻¹ s⁻¹...
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