Study of hydrogen diffusion in superprotonic ionic conductors, MHXO4, by μ+SR and QENS

Published

February 21, 2009

Author(s)

Yutaka Ikedo, Hiroshi Nozaki, Masashi Harada, Jun Sugiyama, Taku J. Sato, Yasumitsu Matsuo, Kusuo Nishiyama, James S. Lord, Yiming Qiu, John R. Copley

Abstract

In order to clarify the mechanism of high proton conductivity (σH+) for superprotonic ionic conductors, MHXO4, where M=Cs and Rb, X=S and Se, muon-spin rotation and relaxation (μ+SR) and quasi-elastic neutron scattering (QENS) measurements have been performed at temperatures mainly in the vicinity of Tc, at which MHXO4 undergoes a structural phase transition from a low-T orthorhombic phase (Phase II) to a high-T tetragonal phase (Phase I). The μ+SR experiment shows the presence of muonium (Mu) state even in Phase I only for CsHSO4 (CHS), while no Mu state was found in Phase I of CsHSeO4 (CHSe). Considering the fact that the σH+ in Phase I of CHS is more than 10 times larger that of CHSe, this implies a relationship between the presence of the atomic hydrogen (Mu) state and high σH+ in Phase I of CHS. According to the QENS measurements using a single crystal of CHSe, line shapes of the energy spectra along three crystallographic directions are found to be slightly anisotropic in Phase I, in contrast to the isotropic conductivity reported by AC conductivity measurements.

Citation

Nuclear Instruments and Methods in Physics Research A

Volume

600

Issue

1

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.nima.2008.11.052

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Keywords

muon spin rotation, relaxation, quasi-elastic neutron scattering

Citation

Ikedo, Y. , Nozaki, H. , Harada, M. , Sugiyama, J. , Sato, T. , Matsuo, Y. , Nishiyama, K. , Lord, J. , Qiu, Y. and Copley, J. (2009), Study of hydrogen diffusion in superprotonic ionic conductors, MHXO4, by μ+SR and QENS, Nuclear Instruments and Methods in Physics Research A, [online], https://doi.org/10.1016/j.nima.2008.11.052, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=610081 (Accessed October 14, 2025)