Spin Depolarization of Muonium in Mesoporous Silica

13th International Conference on Muon Spin Rotation, Relaxation and Resonance

Dehn, M.H.^1 ; Arseneau, D.J.^2 ; Bridges, M.D.^3 ; Buck, T.^4 ; Cortie, D.L.^2,4 ; Cottrell, S.P.^5 ; Fleming, D.G.^2,6 ; Kelly, J.A.^6 ; Macfarlane, W.A.^2,6 ; Maclachlan, M.J.^6 ; Morris, G.D.^2 ; McKenzie, I.^2 ; Xiao, J.^6 ; Kiefl, R.F.^2,4

Physik-Department, Technische Universität München, James-Franck-Strasse 1, Garching bei München

85748, Germany^1

TRIUMF, 4004 Wesbrook Mall, Vancouver

BC

V6T 2A3, Canada^2

Department of Chemistry and Biochemistry, California State University, Fullerton

CA

92831, United States^3

Department of Physics and Astronomy, University of British Columbia, Vancouver

BC

V6T 1Z1, Canada^4

STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot

OX11 0QX, United Kingdom^5

Department of Chemistry, University of British Columbia, Vancouver

BC

V6T 1Z1, Canada^6

关键词: Diamagnetic state;    High specific surface area;    Measurements of;    Mesoporous Silica;    Muon spin rotation/relaxation;    Spin exchanges;    Uncapped Nanoparticles;    Very low temperatures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/551/1/012006/pdf
DOI  :  10.1088/1742-6596/551/1/012006

来源: IOP

【 摘 要 】

We report muon spin rotation/relaxation measurements of muonium in mesoporous silica (SBA-15) with a high specific surface area of 600 m2/g. Up to 70 percent of the incoming muons form muonium and escape efficiently into the open pores at all temperatures between 3 and 300K. We present evidence that the interaction with the silica surfaces involves both spin exchange and a transition to a diamagnetic state, possibly due to dangling bonds on the surface. At very low temperatures, below 20K, the interaction between muonium and the silica surfaces is suppressed due to a He film coating the surfaces. These results indicate that it should be possible to use muonium to probe the surfaces of uncapped nanoparticles supported in silica.