Location of the H[+/-] level: Experimental limits for muonium

The defect energy levels for muonium, a light pseudo-isotope of hydrogen, are investigated to define the equivalent of the H[+/-] level which is predicted to be fixed at a universal energy. Existing results for Mu at donor and acceptor sites in silicon tentatively place Mu[+/-] approximately 0.5 eV above the predicted hydrogen level. Measured donor ionization energies in other materials in which two neutral Mu centers are observed define a range for the Mu acceptor energies. We discuss possible reinterpretation of known energies and the current state of investigations to obtain these muonium acceptor levels in order to further refine a determination of the Mu[+/-] energy.http://www.sciencedirect.com/science/article/B6TVH-4J3NYBD-15/1/4a9b436914b8289c0cb949279f64cb8

Experimental evidence for a Mott-Wigner glass phase of magnetite above the Verwey temperature

New muon-spin-relaxation (µSR) results on magnetite are reported and discussed in light of earlier Mössbauer, neutron, and µSR results. Modification of the µSR anomaly (observed at 247 K in zero field), when an external magnetic field is applied, provides evidence that the anomaly results from cross relaxation between the muon Larmor precession and the electron-correlation process in the B sublattice. The combined results strongly indicate that phonon-assisted electron hopping is the principal conduction mechanism above the Verwey transition temperature (TV). Together with theoretical evidence, these data support Mott’s suggestion that above TV magnetite is in the Wigner-glass state

A μSR study of valence fluctuations in Fe3O4

New µSR measurements on Fe3O4, showing a temperature shift of the "247 K anomaly" in applied fields, demonstrate muon-conduction-electron cross-relaxation and yield a 0.11 eV barrier for near-neighbor B-site electron transfer above the Verwey transition. µSR relaxation rates and the possibility of molecular-polaron formation are discussed

Observation of the anisotropic spin-glass transition and transverse spin ordering in pseudo-brookite through muon spin relaxation

Zero-field longitudinal muon-spin-relaxation (µSR) experiments have been performed on single crystals of pseudo-brookite (Fe2-xTil+x O 5; x=0.25), an anisotropic spin-glass system. The spinglass temperature (Tg) is determined to be 44.0±0.5K. Above Tg, a distinct exponential muon-spin-relaxation rate (¿) is observed, while below Tg a square-root exponential decay is seen, indicating fast spin fluctuations in the ‘frozen’ state. Near 8K, a maximum in ¿ is observed, which is due to transverse spin ordering at these low temperatures. Even near Tg, ¿ is very low

Shallow donor state of hydrogen in indium nitride

The nature of the electron states associated with hydrogen in InN has been inferred by studying the behavior of positive muons, which mimic protons when implanted into semiconductors. The muons capture electrons below 60 K, forming paramagnetic centers with a binding energy of about 12 meV. Together with an exceedingly small muon-electron hyperfine constant indicative of a highly delocalized electron wave function, the results confirm the recently predicted shallow-donor properties of hydrogen in InN

Possible donor and acceptor energies for Mu in ZnSe

http://www.sciencedirect.com/science/article/B6TVH-4V2NP2J-1G/2/9cc872ab4bb7b3920fd0a305f17d770